Question

...but other good reason to make a Hero early is so you can automatically drop some early job skills for other things because you won't ever use it again anyways. Skills like powerstrike and perhaps brandish that you won't ever use again because they'll be completely replaced.

This can be done, but I would consider Balrog and any other future skill-restricting bosses before doing that. In reality, the skills you would get in place of those would be Iron Body and MP Recovery, both of which are less useful that the rest. However, if no higher skill-restricting bosses are added, Brandish could completely be skipped. I myself won't be taking that chance, but you on the other hand may not want to fight Balrog or any boss of that sort. It's how you want to play your character.