Smaller parties make for a more tense and fun experience.
If we had 6 combat would feel pretty boring and honestly too easy.
Also as a player getting to play with a different party i think is pretty nice too.
Playing more of a frontliner i dont have to deal with the cranky Gith all the time now and i get to experience the pleasure of a bi-sexual vampire who wants to eat me. I would have missed out on that experience when i was a rogue