I don't know if I like the idea of Vapor being used in general WATER decks, though. But it would have made Anki much less powerful. That being said, if it's enough of a problem, they could easily just limit Anki to solve the issue.
I get that. But I think Mask Change II's versatility outweighs Mask Change's OTK potential overall. (I also don't see limiting Anki as a big deal.) It would also reduce the chances of any other Masked HEROes being released, since any deck could potentially break them. (That being said, Divine Wind and Dian are the only ones that really have any shot of coming anyway, so I guess it doesn't matter.)