Percy has already lead a war, and we all already love him. Jason has no base line for a character other than he knows his father is Jupiter/Zeus and he can summon lightening and has a gold sword. But Percy has been through 2 quests, one that wasn't even his and he saved Olympus from pure destruction from the Titans. Now, It may be true they should work together, both camps, because that's the only way to destroy whatever comes there way. But I'm not sure Jason and Percy together leading 5 people would work.