For people voting to keep Nanites, note that it's noted multiple times that it's requires lots of power. We're mostly running on conventional power sources, which we get away with by combining machines with their own power sources, and using powerful one use Batteries for finishers. We can't effectively use the Nanites without getting our own Super Science Power Source.
Really Fulgur Particles and Nanites are more or less a package deal as only the Fulgur Particle Engine really brings the power to make the full use of the nanites. As far as the regeneration aspect goes, I think we're actually getting closer to K-Tech based regeneration looking at what the K-Mesh 2.0 is capable of.