I love the slimmed down 4-player party. I despise the idea of having every available option to handle any situation that may come my way. I want to have to make an intelligent and involved decision on how I'm going to round out my party for whatever my intention is during that playthrough. I don't need the "perfect" game where I pass every skill check, unlock every door, or persuade every NPC successfully. I enjoy playing through a dense game like this multiple times to see how different setups and characters react to each other. I feel as though being forced to have access to that all at once would somehow cheapen the experience for me. I'd likely intentionally make two characters as useless as possible or keep them at my camp so that I wasn't provided so many options.
I don't want to fall to bits 'cos of excess existential thought.