I'm a PuG grounder. I'm pretty decent at it too, not the best but I'll tear though quite a bit of my competition. So when my team encounters an actual Fleet team in PvP, I groan and think, "Oh ffs, they're here to powertrip again."
I think it's player attitudes that's the problem, not the game. Sportsmanship isn't very widespread in any PvP game, and this game is no exception. Sometimes you have to stand back and wonder if you're taking your dominance of any given round too far. It's actually OK to throttle back, providing you don't do it too much for risk of looking cocky ("Oh look, I don't have to even try with you... hur hur hur...").
I just find with established teams that the attitude is not to play fair, but to dominate. If that attitude could change, perhaps save it for matches that actually matter, you might find the PvP environment a bit better.
I hear what your saying, but I really think that as stated before, the game is plagued by huge skill gaps due to design. I've "throttled back" before in matches by not participating at all and leaving my team short a guy. Problem is perception though. Like you said, you don't want to seem cocky, but what looks cocky to one team may not to the next team. Beating a team 4v5 while I sit by can definately look cocky to some people while others may thank me for it. In the end though, my team will win. I won't sit by on the sidelines if we start to lose because we're down a guy.