Can't stand all of these things, to be honest. It should still be possible to take them with you together and exactly because of their rivalery/whatever there should be interesting situations because of it.
For me, it's just arbitary and the game saying "No, you can't do that. Here's exchangeable story reason #234343442.*
The game should encourage taking different companions with us by providing lots of reactivity. For example, you get a quest where one of the solutions is a sneaky one. So, for one if you bring two people that hate eachother their quarrel could result in you being detected. Or......
Possibilities for reactivity is endless (naturally too much to really account for everything. Don't expect that though)).
So, the content itself should give me reason to assemble a certain team (and give me corresponding results if I'm doing it differently). This shouldn't be forced by preventing me to try something.