If you get to over lvl 85 and haven't decided to farm any of the legend's then why should you have as much chance as the person who has.
I have a lvl 85 farm Luke, storm han,
That's 20k gp that I've had to pay to get CLS.
Surely if someone has gone to the effort of doing heroic sith with their guild they should have an advantage.
I would say though that being able to hide teams whilst adding strategy does create a more negative experience as your opponent is stuck behind a power form. As opposed to being able to have 5 battles with one they can't get past.
But if someone deliberately keeps their GP down for GA they do worse in TB etc. You can't have their cake and eat it.
EDIT: also GA is precisely where toons like Aayla and Lando Rock. My gear 11 Aayla and 10 Lando are stars who trash an underdeveloped b/c team.