What if the max guild size was 25 instead of 50?
It would be much easier to manage, organize, and maintain 25 people toward a goal than 50.
You'd cut the fights in TW, so the time issue goes away again.
Not only that, for starter guilds, they'll actually get TW launched as fielding 12/13 instead of 25 as a minimum is easier to meet.
Raid health totals gets adjusted downward as well.
I've seen other games (World of Warcraft) make a change like that and it proved to be for the better there too.
Just a thought.