I'm sure we'll get ESB and ROTJ Vaders and possibly even ROTS Vader. Hopefully those will see Vader a bit more in scale with normal 1/6 stuff and less in DCD 13" scale.
I'm very mixed on that idea. On the one hand, I care more about those Vaders than ANH so that improvement would be welcome, but on the other hand, the difference would probably be fairly clear that ANH and the others aren't the same size, and to me it'd be a little strange to have a figure made by the same company and significantly inconsistent in size. Jedi Luke is a hair taller than the others, but basically all the same height on the short Buck, same with ANH and Bespin Han. I guess in the end I'd be happiest just having a ROTJ Vader looking sharp and proper size to Piett and Palpatine.