How hard can it be to put just one more character in and make it five?
It is already implemented. When you start a custom 4player Party you can have 5 and possibly 6 people in your party (your 4 customs + Laezel + Us)
It is a conscious decision and has absolutely nothing to do with Larian being lazy or any of the other "reasons" people give just because they are salty about it.
