I don't see that as a problem. That's part of endurance racing. That how it is in real life, finding a compromise that all the teams drivers can drive.
All I would ask is that they provide the facility to choose individual setups for each driver then it's up to individuals as to whether they choose to use it or not. It's these little details that make the game more accessible. If they go too far down the "hard-core" route they alienate people. If you want to run the same setup as your team mate, that's fine, but why remove the flexibility for those that don't have much time to work on a common setup. This is a game after all, one which most of us have very little time to play.