What draws so many people in to comics is the idea of peeking inside a world where we're all just a freak accident or a magic ring away from soaring through the air. It also helps that funny books are an environment in which writers can craft tales where literally anything can happen.
However, just because you can do something, doesn't necessarily mean you should and that is often the case when trying to change iconic characters.
Over the course of decades of stories, it's only natural that writers would occasionally want to shake things up to keep characters from getting stale. The problem is, so often they completely dive off the deep end and try to reinvent the wheel, with results more disastrous then that attempt to mix metaphors.
Changes will be made that completely undermine the whole point of a hero, or maybe they'll get bizarre new powers that don't mesh at all with who they are. Heck, sometimes even a simple change of costume can completely derail a character.
And then other times Batman gets turned into a toddler.