I do agree that V4 seems more of a side grade then an upgrade from V3, but having said that I do like V4 as a additional alternate figure, I do like her look. With V3, V4, Jessy, Sydney, Miki, SP3, L3 and A3 I find I have  a great range to choose from for diversity.  Now being a huge A3 fan I found A4 on the other hand was a huge letdown. 

Now M4 I am not sure on, I have M2, M3 and all them G2 gents and I haven't even tried them all yet. Don't think I need another figure that I will never use. I would rather see a huge increase in items and clothes for M3 and perhaps some more diversity morphs.