Assemble the Legion is something that I keep wanting to try to build around, but it's SOOO bad. I think the only way to make it work is to get value out of the tokens as they enter the battlefield, something like Impact Tremors, but ideally something that can kill your opponent's creature. Maybe just giving them deathtouch somehow would work. You just REALLY need a way to protect yourself for a few turns after you play it. Prison might be an option as well, anything to lock down your opponent long enough for the card to build up counters.