I just had such a cool idea for the knight level. Instead of a broadsword, give him a one-handed sword and shield, that has more than one attack, like magic. The way it works is this: Z is your standard attack, and X is a big two-handed swipe (DON'T ask how you can hold a two-handed sword and a shield at the same time, cos shields are normally strapped onto a person's arm leaving the hand (almost) free), unless someone attacks you at the same time, then X is parry-riposte (block and attack back for any1 who doesn't fence).
Alternatively, if that sounds like too much, you could make Z attack and X defend (like the normal down shield but direction-based (so you can still be hit from behind) and without a time limit (so your opponent can pump as many rounds into your shield as he likes, it won't wear off). Or maybe the shield should be capable of taking damage independently of you...
In any case, please say which idea you prefer.