Hey man! Glad you’re coming back. I returned about six months ago and it has been an absolute blast.
Things are great! I’ve been on again and off again on MG since Wrath, and I have to say that every time I leave and come back, the RP community is even more inclusive and supportive than they were before. Not that I ever ran into any problems in days past, but I have heard stories. Suffice it to say that, regardless of whatever type of character you’re looking to play, I’m confident that you’ll be able to find other players, or even a guild, that works for you.
As for Alliance RP hubs, there’s basically Stormwind City, and Darkshire, and that’s really about it. My friends and I have been bringing RP to other spots as much as we can, namely Boralus and just today in Booty Bay, but it’s literally just the 3-6 of us each time. And we’re all people who met in Stormwind over the course of like 6-8 weeks, so it took time to build the relationships and then to start venturing out. But in my experience, everyone wants to RP outside of Stormwind, it’s just that they need a specific reason to.
And for server canon? I don’t think there’s any established list of canon beyond what the game provides and then each person’s/group’s/guild’s accepted canon. You’re pretty much free to do whatever you want and claim whatever you want as canon on your own, just be prepared for people to not want to RP with you if you get too outlandish with stuff.
All in all, I personally feel like MG Alliance RP is the best it’s ever been. As I said, I’m glad you found tour way back, and I look forward to bumping into your toons in Stormwind one of these days!