At least for me to add explanation on what I said earlier, I feel four is way too few because usually most games just go with the safe core four party archetypes and don't even bother to deviate or add anything unique.
At least with a bit of a larger roster if the devs care, you can get some more creativity or underutilized archetypes or roles and add variety.
Formerly Gamenamebully.
Still only Sane gamer.