Can I suggest creating an item specific actions (equipped weapons means attack controls, equipped shield means block controls). M1 and M2 could correspond with left and right hands of the character.
Brink used a very intuitive system for evasive maneuvering. If you added attack controls to a system like that, I imagine it could be a lot of fun.
You might try a toggled movement system as well (Double tap W key to toggle moving forward). The reason for this is the ability to look in a separate direction from the direction you are moving (really useful for using melee weapons) and could make a targeting system really interesting.