I have a suggestion that would make this game mode about 12 times as good. Enable players to outift an an archer character, an infantry character and a cav character, using a limited amount of money, but with build entirely free. Of these customizable class archetypes, 200 will spawn aaaaand fight.
You know you want to see 100 full strength Flamberge wielding Gothic Knights charge at 100 full strength Great Maul wielding Gothic Knights. Or go nuts and blow all your budget on plated chargers. What a brilliant game mode would that be.