I like those sorts of choices, but right now the big 'choice' between party composition is whether you side with the goblins or the tieflings, and so far (keeping in mind what we know from datamining on the identity of the remaining origin characters and some specific dialogue lines Karlach says) It looks like you lose half your companions/romance options by choosing one option, & don't lose any companions or romance options by choosing the other option. It's rather baffling that it's presented as a choice at all.
We know there's another cull at the end of act I that will result in our 'final' party, which makes me wonder if post act-I if we are going to have any real sort of party conflict where we have to choose one character over another.
I really enjoy how dynamic party compositions can be in other rpgs, so I hope we get more conflicts/choices post act I, but I also hope we have more party members available to join after act I as well to shake the dynamic up a bit (particularly if they go with the Act I party member cull that's been talked about). And I really hope our major choices later in the game don't so blatantly favor good-players down the road, because honestly the whole goblin/tiefling dilemma right now is really awful (IMO).