Ah. I see (reading your post again). My fault. I interpreted it like you were saying the P7 got too much bass - which you are not necessarily saying.
I haven't tried the H6 myself, but yes - that seems to be the consensus.
I prefer the HP50 over the P7 when it comes to bass, but I wouldn't want it to be any less bass than what the HP50 got.
If 5 was the perfect amount of bass on a scale from 1-10. I would give the HP50 a 5 and the P7 a 6. I would rather have a headset with 6 than 4 though. The Momentum would be a 6.5 maybe 7 - and would basically be the outer limit for acceptable bass in my opinion. Anything beyond 7 just becomes annoying. H6 definitely sounds like a 4 or less from the reviews I have read.
All down to personal preferences I guess. I wish the P7 had slightly less bass, but it also makes some tunes quite fun to listen to. Anything less than HP50 would be boring to me - and I don't really listen much to "bass heavy" music, but especially some metal (like Tool) loses some of its feel if the bass is too subdued.