Oh no, I agree. The Teamwork aspect is 100% working as intended. It's actually the whole point of the "holy trinity" in MMO design. It ensures that Teamwork is required to complete any dungeon, and that each player has a distinct role to play in the team.
However, that heavy emphasis on teamwork also makes judging individual performance, let alone tying rewards to it, far more difficult.
I can just imagine the salt threads about "missing rewards" thanks to a crappy team.