The problem is that GP isn't a real indication of the power of someones rooster. Even if you just count chars and not ships it wouldn't match equal opponents together.
e.g. one player levels all new toons up to 50 to save the mods somewhere instead of selling them because of this limited mod space he will have a much higher GP value than he should compared to another player who concentrates just on a few teams etc.
The other issue with GA is that it gets very boring and annoying over time 'cause it feels like work instead of a game. We have (had) christmas, and playing up to 11 battles every other day (if you just need one fight to win of course) is a lot of time you'll need, beside arena, tb, dailies and so on. If there is no significant change in the kind of competition of GA it may end like ship arena battles which most of players ignore!