Er...multiclassing the Vampire is a bit natural, isn't it? I mean, your fighter/wizard/rogue gets bit (or starts drinking weird concoctions; whatever); and develops a pale look and a hunger for human/elven/mimic/air elemental (yeah, that's the aspect to vampires that bothers me a bit, though I understand the reasoning behind it) blood...
Letting people swap in to/out of Power Strike seems very cool -- though I'm a bit bothered by the implication of a feat cost, given that PS has more or less exactly the power of an encounter power. I guess it might work as a feat for letting you take encounter powers instead of PS (for an Essential Fighter with more control, or an Essentials Rogue with debuffs instead of backstab), but...
Letting people swap in to/out of Power Strike seems very cool -- though I'm a bit bothered by the implication of a feat cost, given that PS has more or less exactly the power of an encounter power. I guess it might work as a feat for letting you take encounter powers instead of PS (for an Essential Fighter with more control, or an Essentials Rogue with debuffs instead of backstab), but...