I don't see any issue with martial power 2 (though more than 2 would be a stretch). There can still be at least 1 more built for each class, maybe even two, and you could use the rest of the space for martial-themed subclasses like the weapon style multiclass feats or perhaps mounted combat. And ofc it helps to cover the new races for martial classes. Arcane Power II seems a no-brainer as well.