You're still matching by GP. So, you'll have the GP match making issues. Especially, now where we are forced into getting everything new to keep up with the Joneses, we really can't use GP to match make in this high bloat environment. We've all got so flabby, it's highly inaccurate.
Also, players that know what they're doing and have a good read on the meta can take out rosters 3 times their size.
The only way I'd like to see any form of GP match making, is if players who are considerably larger GP than the division average are placed in their own pool. There's obviously issues there and so they could be matched together.
I think though, I'm sold on this 'activity score' idea. You gain or lose a point depending on how much you interact with your GAC match. After a while, you'll have a score that's represents your general GAC activity. Then you'll be paired with players with the same Skill Points and are just as active as you.
I'd like to see that added and give it a while, see what happens to the environment then.