I'm not sure I understand. If the game is calibrated so that the main character can go multiclass, while the rest of the party has fewer points, forcing them to stay single class to keep up, is there anything in the game you'd want that would keep the main character from also going single class and just being stronger than the rest of the party? (Am I getting you right?)
No, there's nothing to keep the PC from going single class and being very good at it. It's a choice - between being very efficient as a single class character and efficient as a multi-class character.
Yeah I hadn't considered drop-in multiplayer. That would be problematic. Maybe... a Lone Wolf trait that specifically gives twice the ability points but no other bonuses?
