I think Spidey has had many more suit changes than any other hero. Among the most ridiculous I remember the paperbag incident, the pink and light blue washout spidersuit and the one from the cartoon show from space.
I don't know about that. Maybe male hero. Wasp and Kitty Pryde come to mind. Iron Man changes quite a bit too. Although most of Iron Man's pretty good.
Yup, you're right the Wasp changes a lot, since I don't follow the avengers, I had forgotten. Ironman changes but they look very alike, and in reality the change it;s up to the artist they use for the run. When Spidey changes the artists have to accomodate to the look. Kitty pride? not as much, look at rogue and she hulk.
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Try not to stab your eyes out.