From side rooms, you would save yourself a lot of rage chat, unless they decide to pm you.

People can still socialize through pms, gc, and main lobby (the chair lines area).
Most of the time I am quiet in spar, don't really have time to talk, unless it's through pms.

Otherwise, I'm not following with "the social aspects of sparring". The spar rooms are mostly for spar. Obviously there are people who afk/chat with their friends, and watch matches, but the community can still socialize outside of the arena (Not the building).

Honestly though, I wouldn't mind not being able to watch matches, but you could just allow people to spectate current matches. Not sure what type of matchmaking system you are referring to, but if it's tier based, then you can have top sparrers matches at the top. Maybe like a replay? Clash Royale style.