Let's analyze the VEs:
Iron Man - carbon copy with improvements
Spider-Man - carbon copy game, new art. Based on Jody's comments, they wanted to the VE based on the movie trilogy and Disney suggested a cartoon version...I'm sure Disney didn't want to give Sony a cut.
Batman 66 - new rules, half the playfield redesigned, SPIKE instead of SAM...can we say this is a VE or a re-imagining?
AC/DC - IMO, the only thing stopping this would be AC/DC themselves. I think Stern could easily run an additional 500 Premiums (few of them LUCI) and another 1,000 Pros and all will sell out.
Tron VE - make it like Iron Man VE, but add lighted ramps. Stern should be able to sell 750 of these.