One summon per person limit basically cripples/makes the extra summons in the game like the black cat very weak or not useful, you naturally want all the summon abilities on the summoner with the best summon stat, but it's worthless because they can only have one out at a time.

It's very much a cardinal sin in regards to summoning classes, whose strength is thriving on being able to have an army at their disposal. Maybe these secondary summons ought to be changed to scale off a character's highest combat skill so they can be freely distributed. It's almost laughable that for example a necromancy school summon requires summoning stat to scale its usefulness. It'd be like if combat abilities did not switch between finesse and strength depending on which is higher for the character.

My biggest disappointment is not being able to have controllable void beings. I personally don't like the look of the incarnate much even at its highest form. It's versatility is nice, but the armor it has is too tacky, I wished for something more terrifying, monstrous, and bestial.