Considering how many actions a single character can take during his/her turn, I'd rather prefer a single (more versatile, lasting and interesting) summon per party involved in the fight.
8 characters with 2-4 actions per turn? Definitely a terrible idea in my book.
Agreed. I thought I had said this in my previous answer, seems like I forgot. 8 characters would just feel very, very, very slow and every turn would seem like they take an eternity.
