150 leadership is not hard to get imo. You have left out how many points you have put into leadership and social, as this might be the cause of your problem. If not that, just lead armies. You can Take one of your companions and make a party with them, fill them up with troops from your own party, create an army with just you and them that you maintain indefinitely, and your' Army' will just be comprised of and function the same as your previous party except now you're slowly gaining leadership. Or you have 3 companions/relatives form full parties, invite them, move slow but level up leadership faster.