I killed a entire map with Shadow just with 1-hit-kill throwing knifes and punching them to death with Dusters. PLaying in extreme.

The second idea is to conserve APs. I.E. you press a button or a key at the start of a turn (only at the start!) and immediately lose all of your APs. However, on the next turn, you have double the APs to use! The extra AP can only be spent on movement. This allows you to "sprint" at an enemy with 100AP, then use the remaining 100AP to beat the crap out of him or slash him up good. This allows you to cover the last few feet towards an enemy and not end your turn a sitting duck hoping he doesn't kill you the next round. There are several problems with implementing this though.