Well, you would've guessed wrong, seeing as XML1 powers leveled up completely differently, used separate models for entities, had LOTS of effects that needed recoloring, and, in some cases, used different handlers that don't exist in XML2.
boreman: Inserting the files will result in most chars working properly, it is the balancing (energy, damage) and the lack of certain handlers in MUA (Mystique's shapeshift, Bishop's gun), as well as the custom powers that are super time-consuming.