Kirsten Dunst isn't my favorite actress either. I just *GASP* enjoy her performance in the movies and don't think they should replace her! Why is that so radical?
I don't buy into this silly "GWEMJ" thing. I think Dunst's Mary Jane is in line with her comics counter-part, just because she's not a superficial party girl, doesn't mean her character is unfaithful to the comics. They just incorporated more of the growth and depth Mary Jane gained over the years.
I really don't see any of Gwen Stacy in it at all. But if there was...maybe people like Doc Ock could stop whining about it.