what wrong with this?

[DioShiba]

Should I add a rule saying not to post sprite edits

and explain what edits are
because I'm thinking I should

no

just like with recolors, edits in general aren't bad

kind of depends on what kind of edit it is though

If it's a simple, shitty one like this, then that is frowned upon here.
If it's a heavy edit, meaning that you've edited every little detail on the sprite to differ it from the original sprite then that's alright.

really, editing should be explained, but only if it defines what kinds of edits should be done, just sayin.