Charizard fast move

Imho fire Spin is better. The only mon that resist Fire and Dragon is Azumarill, but you wont see him in Ultra League often and even much rare in Gyms.

Fast TMs are not as important as charge TMs. Usually only need one fast TM to switch to a desired move, so they tend to pile up more.

Go ahead change it to Fire Spin to try it. You can change it back easily enough if you liked it better the other way.