I also have a question about Guilds, namely the Architecture development tree. Since it's insanely expensive to get the upgrades, and there's at least one empty level, is it safe to assume that raising a Guild's Architecture level has a visible impact on its aesthetics and/or layout?
There is currently no guild hall, so no. There will eventually be guild halls, but they weren't as important as existing variation of PvP and overall function of guilds for release. They've had a few interviews concerning what they weren't and were implementing, and guild hall fall under the chopping block of desired but unessential for release game play. They may or may not repeat guild battle from Guild Wars 1, but they want and we expect more from them than just private instances for guild members to visit.
With that said, Architecture affects shared storage and construction abilities. Politics effects the Guild Emblem and our ability to purchase the transmutation stones to display it on our gear, plus most the boost to increase influence gain. Economy includes the rest of the PvE boosts. Finally Art of War has one PvP influence boost, and a bunch of WvW boost we should only be concerned about if we all end up on one world.
The assuming a social guild means I'm assuming the communal sharing abilities of the guild bank is important, along with the ability to represent our guild. The PvE boost can be important as well, but only if we have enough interested bodies to organize a guild game day. Most the PvP boosts are regulated to controlling at least a tower in WvW, with the PvP influence boost only viable if we want to organize a guild game day for PvP.
It's a lot of assumptions, the resolution of which would require discussion. I'm pretty sure most of us just want to play the game, but the guild will be earning influence as long as we represent it while playing. So at the very least there should be some discussion. I'd motion that Architecture 2 with the workshop and guild bank should be one priority, with Politics 2 with the guild emblem and armor contracts being a parallel priority. Once both of those are fulfilled... well that is part of the discussion.