I really feel as though [url=https://www.roleplayerguild.com/posts/4806687]this thread[/url] from two months ago already covered this topic in its fullest. Anything here is going to retread that ground.

But for the sake of adding my own thoughts, a GM shouldn't feel like they need to conform one way or the other. If you as the GM don't care about character sheets, then, by all means, run your roleplay without them, but if you do like them for any number of reasons then yes require one. If you as a player don't like filling out sheets, then don't join RPs which require them and if you like filling them out, then good news because even if an RP doesn't require one, it doesn't mean you can't make a personal one.

To summarize, do what makes you happy and what keeps you engaged and interested in your roleplays.