Honestly, there were a couple of times if someone were around to help during my leveling to 10, I would have been happy to take the help. There was one quest in particular I had to wait a couple of levels above where I should have been. I think it was just too hard for the level they specified. They're constantly fiddling difficulties; I've found that out several times along the way, most recently on a class quest that I had been working on for 4 levels and could not complete until they patched it, and it was magically easy.
I know that this isn't going to be exactly like STO. But it's a similar group of people working toward a similar goal. As far as I know, there was no problem with guild size there (or maybe I just missed it). But apparently on SWTOR there is. We're going to have to cross this bridge sooner or later, so we might as well address it now, especially since we're not sure who is and isn't active not even 4 weeks into the release. If this system doesn't work, things can still be done in the future to improve it.
I'm curious, maybe I'm missing something, but what else does splitting the guild do other than make people talk on the Stonewall forum instead of just the Guild chat? That's the only major difference that I can think of that most people would see (well, that and the name that appears above your character). I know in STO, Klingons and Federation talked on the same channel, and it never seemed to be too much chatter; maybe the membership was lower, I'm not the one who has that answer. But based on what I see in guild chat now, even multiplying it by 3 or 4 wouldn't make it overwhelming. Most of the time there isn't chat going on, and when there is, it's usually just a few interested individuals or people just saying hi. Captains/Officers should have multiple characters and should able to easily move among the guilds to add/assist people as needed.