I dig the new change. However, if I were in a squad, I'd be a bit peeved since there's no gaurantee you can get into the arena your buddies are in.
So, how about a Queue? Select your arena, and if its full, you have the option to either wait in line for a spot to open in the arena you desire, or automatically divert to the arena with an open spot. It would be a bit friendlier and not make squad nights a major hassle.
Take it a step further, and I know this would require a client release, but have comms come up as soon as you're logged in so you can find out where to go, or depending on populations, queue up at.
Knowing you've got a 3 minute wait, imho, is a bit nicer than just being dumped whereever and having to quit & rejoin continuously.