I've commented before that there are powersets that can affect what you DO, but there should be more thematic ones that can fit for what you ARE. For example, a "cybernetics" defense set that offered high resistance to PSI and Toxic, at the cost of less protection against Energy.....like if you're either a cyborg or a robot, your mind will be harder to affect, and poisons won't bother you as much, but you have to worry about being shorted out by electricity. Probably some equivalent for Ghosts, plant creatures, etc, etc. Make defensive sets that offer up an edge in certain areas but balance it with less protection in others.