And I think that the game is nearly already balance for it... I won't spoil here but since the beginning, I'm fighting a lot and there are many "huge" battles (I'm inside the goblin camp).
I can deal with those battles with a group of 4 but that's not always easy. I like difficulty but I think some don't.
=> More party members mean less difficulty for this "normal game mode".
Another thing in those huge combat is how slow they are... Not because of TB or because of D&D but when you face 15 ennemies and have to attack at least 4 times or more each one of them (considering all the miss), that's sooo slow.
=> More companions don't mean slower, but FASTER combat because you can kill your ennemies in less turns.
I also notice that there is the EXACT place for 2 more potraits... I hope.