Well I mean there are going to be some who say that no matter WHAT you do, so I wouldn't let that stand in the way of a good name.
But seriously, I don't like Reborn, sounds too much the name of Binding of Isaac's remake. Not that I think there'd be any confusion given, well, everything about the two games, but it still bugs me. How about "Second Wave"? It references the wave mechanics, is a war term, implies it would be both sequel and more of the same, and that things will be bigger.