4 party size is probably due to fear of too long turns, while also maintaining a 4 man co-op.
It is entirely 100% due to co-op, because co-op is their priority over single-player. Every game building decision Larian has made has been first and foremost about how it affects co-op, and about what is best for co-op, SP be damned.
That may have been their thinking, I can’t comment on that. But I’ve never played a co-op game in my life and am not particularly likely to, and I like a party size of four. I enjoy finding different combinations of character classes and ability/spell selections that can cover essential roles, or finding alternative approaches to solving problems when I don’t have perfect coverage. For me, this enhances replayability.
I can completely understand why some folk prefer larger party sizes, but I don’t think it’s anywhere near as simple as single-player vs co-op.
EDIT: With respect to this …
Originally Posted by RagnarokCzD
Originally Posted by Anaz
4 party size is probably due to fear of too long turns
IF that is true ... Then its wrong ... as it was several times prooven.
The current fights shouldn’t be any longer with six party members than four, but if party size were to be increased by default then I do hope that Larian would rebalance the encounters to make them harder, which would I think also make them longer. Otherwise, you just end up with each character having fewer turns per battle, and that I wouldn’t like.