Since this is a general forum, I thought I'd pose this question here:

Was having a conversation with my friend on superhero history and the evolution of superhero costumes. We were talking about DC's decision in the early 2000s to retire the yellow oval Bat signal in favor of the black bat, Superman's varying cape lengths and \S/ shield sizes, then the decision to give Superman armor and removal of ALL trunks in the NEW 52, Billy Batson's costume change with the addition of the hood, Captain America's change from the Kirby model to a militarized Flag costume, Spidey's alternate and varying costumes over the years, the changes in the X-men & Fantastic Four costumes over the years, THE LIST GOES ON.
My question is: Should iconic costumes be messed with as part of character evolution OR should the classics stay as they are to preserve tradition?
If they should be changed, HOW MUCH IS TOO MUCH?