1)a massive 2 handed hammer user
2) someone with a pet (their abilities are pet based)
3) mounted characters (not a speed bonus just someone riding a cool beast.
A death match mode - maybe disable leveling up, to keep it more streamlined?
Invasion/Defense mode- 2 rounds, one team defending the other invading. Only invaders get minions, defenders get access to a lot of towers.
These would be cool additions.
Post more ideas people!