Compared to every RPG ever made with 3-4 party members, this is truly a small number. SO many Crpgs have 4 or less party members. That was my point and why it doesn't bother me. Would I like 6 or more? Absolutely, but having 4 is not uncommon.
Why don't you compare it to other RPGs of THE SAME TYPE if you want to have a pertinent limitation, then? How is the number of party members in something like Final Fantasy or KOTOR even relevant at all? What's next? Persona? Gothic and Risen, where you play with action controls and third person camera in solo?