In comparison the costs are about the same between melee and ranged. The difference is that whatever ammo you use is now in the melee weapon/amp decay. Defensive costs might go up at first if you shift, but that is understandable if you are suddenly hugging a creature instead of shooting it at ranged. For some it takes finding the right mob for the setup to feel more confident about playing melee. About the amps, nothing has indicated that there will be a shift in melee. There is a chance there might be more people leaving melee combat in favor of ranged, or melee weapons/amp might see the same drop in MU as often enough other weapons have before and after MM.