Let me preface this by saying that I am an academic, a professional student, and tend to approach all things with a critical eye and a desire to categorize and understand what I enjoy and participate in. Probably because I'm a music theorist. (As one of my supervisors likes to say, I'm more of a lumper than a splitter.)
Now that I have three Gallifrey One conventions under my belt, I'm beginning to notice a few things. Like how even though it is one giant convention, it really does seem like two conventions going at once.
Here's what I mean.
Attendees of the Gallifrey One convention seem to fit into one of two categories: fantasy!fandom/fan-production and critical!fandom/author-production (when I say "critical" I really mean critics/criticism, and in a constructive way, like a film critic or music critic). To say that they're mutually exclusive is unfair, as there are plenty of people that find themselves interested in both. When I use the term fantasy!fandom I mean costuming, cosplaying, fanfic, crafting, and other types of fabrication that are inspired by Doctor Who, its spin-offs, and SF in general. Those that fit into critical!fandom (or production!fandom) attend writing/directing/producing panels, actor interviews, and are more engaged with the show as a text than as a site for creating fantasy or positing character development/etc. outside of the show's diegesis (though these are very clearly critical engagement, just from a different angle). Clearly there are people that fit into both categories; I think people that have had a hand in producing the show and attend conventions also fit into both, especially people like Toby Haynes (who attended in 2012) that participated as a fan and producer. I also think podcasters fit into both categories; they create their own content based on criticism.
Edit: I've added terms in bold that may be a better representation of the point I'm trying to make. I won't rewrite this article, but I'll add terms that more adequately express what I'm trying to say. Thanks for the feedback to those that have provided it!

Where do I fit in? 110% critical!fandom. The appeal of making costumes based on characters, doing crossplay, etc., is totally beyond me. Do I hold it against others? No way. Love seeing cosplayers! Most of the pictures I go after are clever costumes. But could I ever dress up as Idris from "The Doctor's Wife"? Or build my own K-9? Nope. Not my bag. But a panel on types of cameras used in studio in the 60s? All over that. (And with the depth of research coming out lately I wouldn't be surprised if people could fill an hour talking about it ...)
In its essence, Gallifrey One indulges both interests. About half of the panels revolve around author-production/criticism of Doctor Who as a text and the other half about fantasy!fandom/fan-production. It's almost like there are two conventions happening for two different approaches to Doctor Who fannish activity.

If you look at the panels offered at this past convention, you'll see that both cons exist simultaneously and usually indulge different interests. One focused on the diegetic, another on the extra-diegetic.
The breakdown is pretty interesting to me. One could probably argue that one or two could go back and forth between the two, but there's a pretty clear divide between criticism/author-production and fantasy/fan-production fandom in the panels. (And clearly this isn't all the panels; I left off openly non-DW panels, for sanity's sake.) And I do want to point out, and I mean this sincerely, that I use the term 'fantasy' in a totally loving, endearing way. In no way whatsoever am I trying to make one category more important than the other. I find them equally relevant and wonderful fannish interactions with the program. If my opinion really means that much ... (it does to me!)
I think it's safe to say that there are people who go to a convention like Gallifrey One just for the sake of fantasy/fan-production (cosplay, costuming in general, fanfic, etc.). On the flip side, I know there are people that go to Gallifrey One expressly for criticism/author-production. I'm one of those people. And as I attend this convention I really feel like there are two conventions happening simultaneously: one for the criticism and celebration of the show in-and-of-itself, and one that is a fantasy/fan-production con, where people share their creations and musings that go beyond the show itself and individual criticism expressed through interpretation. One that I'm a part of, and one that goes on behind doors I rarely find myself walking through (except the Crafting Who panel, mostly because I like to knit, and the Who Knits group on Ravelry is what got me interested in going to Gally in the first place).
I only point this out because I find it incredibly fascinating. And I doubt Doctor Who is the only show/movie/whatever with a similar phenomenon in its fandom. But Doctor Who presents itself as an interesting example because of its impressive tenure on television, it's undeniable presence in popular culture, and the immense popularity of this convention. 3000+ attendees? That's just incredible.
And I think with a convention of this size, the categorization is crucial to its success. Think of it like a sort of "divide and conquer" idea.
From what I've heard of American vs. British/European conventions, the cosplay aspect is pretty uniquely American. Also most European conventions are a fraction of the size. Bigger and better in the States, right? I don't know. I've lived in Texas long enough now that I just don't question it anymore.
So what's the point of all of this? That no matter if you're more of a critic/production nerd of Doctor Who or you're interested in the nondiegetic potential created by the rich universe of Doctor Who, a convention like Gallifrey One is easily tailored to your interest. And you're pretty much guaranteed to find about 1000 other people who dig the program in a similar way. And another 1000 with a different interest. And about 3000 all together that love the show differently but equally.
All that aside, I'm pretty sure I could crossplay as the Eleventh Doctor and make it work as a teaching outfit. Hmmmmm ....
ek
Now that I have three Gallifrey One conventions under my belt, I'm beginning to notice a few things. Like how even though it is one giant convention, it really does seem like two conventions going at once.
Here's what I mean.
Attendees of the Gallifrey One convention seem to fit into one of two categories: fantasy!fandom/fan-production and critical!fandom/author-production (when I say "critical" I really mean critics/criticism, and in a constructive way, like a film critic or music critic). To say that they're mutually exclusive is unfair, as there are plenty of people that find themselves interested in both. When I use the term fantasy!fandom I mean costuming, cosplaying, fanfic, crafting, and other types of fabrication that are inspired by Doctor Who, its spin-offs, and SF in general. Those that fit into critical!fandom (or production!fandom) attend writing/directing/producing panels, actor interviews, and are more engaged with the show as a text than as a site for creating fantasy or positing character development/etc. outside of the show's diegesis (though these are very clearly critical engagement, just from a different angle). Clearly there are people that fit into both categories; I think people that have had a hand in producing the show and attend conventions also fit into both, especially people like Toby Haynes (who attended in 2012) that participated as a fan and producer. I also think podcasters fit into both categories; they create their own content based on criticism.
Edit: I've added terms in bold that may be a better representation of the point I'm trying to make. I won't rewrite this article, but I'll add terms that more adequately express what I'm trying to say. Thanks for the feedback to those that have provided it!

Where do I fit in? 110% critical!fandom. The appeal of making costumes based on characters, doing crossplay, etc., is totally beyond me. Do I hold it against others? No way. Love seeing cosplayers! Most of the pictures I go after are clever costumes. But could I ever dress up as Idris from "The Doctor's Wife"? Or build my own K-9? Nope. Not my bag. But a panel on types of cameras used in studio in the 60s? All over that. (And with the depth of research coming out lately I wouldn't be surprised if people could fill an hour talking about it ...)
In its essence, Gallifrey One indulges both interests. About half of the panels revolve around author-production/criticism of Doctor Who as a text and the other half about fantasy!fandom/fan-production. It's almost like there are two conventions happening for two different approaches to Doctor Who fannish activity.

If you look at the panels offered at this past convention, you'll see that both cons exist simultaneously and usually indulge different interests. One focused on the diegetic, another on the extra-diegetic.
Criticism/Author-Production | Fantasy/Fan-Production |
Moffat’s Gold: Series 6 in Review Favorite Doctor Who Moments More Magic of Doctor Who Music Move Along, Pond Memories of the Brigadier Sarah Jane is My Doctor Let’s Take it From the Top Miracle or Mistake The State of SF TV & Film Doctor Who, Sexual Tropes and the “Gay Agenda” Big Finish Cast/Director Interviews Kaffeeklatsches | Back to the Pagoda (New Adventure Novels) Crafting Who, Part Two Designing the Perfect Companion Costuming 101 and 201 21st Century Doctor Who Fandom: Cosplay Factor Doctor Who Prop Making 101 TARDIS Wardrobe: Costuming as the Doctor Dressed to Scream: Cast and Companion Cosplay Diabolical Apparel: Villains and Monsters in Cosplay Out of the Hub Closet: Torchwood Cosplay The Rise of Remix Culture I Ship Everybody with Everyone Else in Every Fandom Ever Masquerade Versus Cosplay Interpretive Cosplay and Crossplay in Doctor Who |
The breakdown is pretty interesting to me. One could probably argue that one or two could go back and forth between the two, but there's a pretty clear divide between criticism/author-production and fantasy/fan-production fandom in the panels. (And clearly this isn't all the panels; I left off openly non-DW panels, for sanity's sake.) And I do want to point out, and I mean this sincerely, that I use the term 'fantasy' in a totally loving, endearing way. In no way whatsoever am I trying to make one category more important than the other. I find them equally relevant and wonderful fannish interactions with the program. If my opinion really means that much ... (it does to me!)
I think it's safe to say that there are people who go to a convention like Gallifrey One just for the sake of fantasy/fan-production (cosplay, costuming in general, fanfic, etc.). On the flip side, I know there are people that go to Gallifrey One expressly for criticism/author-production. I'm one of those people. And as I attend this convention I really feel like there are two conventions happening simultaneously: one for the criticism and celebration of the show in-and-of-itself, and one that is a fantasy/fan-production con, where people share their creations and musings that go beyond the show itself and individual criticism expressed through interpretation. One that I'm a part of, and one that goes on behind doors I rarely find myself walking through (except the Crafting Who panel, mostly because I like to knit, and the Who Knits group on Ravelry is what got me interested in going to Gally in the first place).
I only point this out because I find it incredibly fascinating. And I doubt Doctor Who is the only show/movie/whatever with a similar phenomenon in its fandom. But Doctor Who presents itself as an interesting example because of its impressive tenure on television, it's undeniable presence in popular culture, and the immense popularity of this convention. 3000+ attendees? That's just incredible.
And I think with a convention of this size, the categorization is crucial to its success. Think of it like a sort of "divide and conquer" idea.
From what I've heard of American vs. British/European conventions, the cosplay aspect is pretty uniquely American. Also most European conventions are a fraction of the size. Bigger and better in the States, right? I don't know. I've lived in Texas long enough now that I just don't question it anymore.
So what's the point of all of this? That no matter if you're more of a critic/production nerd of Doctor Who or you're interested in the nondiegetic potential created by the rich universe of Doctor Who, a convention like Gallifrey One is easily tailored to your interest. And you're pretty much guaranteed to find about 1000 other people who dig the program in a similar way. And another 1000 with a different interest. And about 3000 all together that love the show differently but equally.
All that aside, I'm pretty sure I could crossplay as the Eleventh Doctor and make it work as a teaching outfit. Hmmmmm ....
ek