Often when I review suggested edits, I see edits that makes the post worse. Typically they changes the format to worse (adding stuff in bold which makes no sense, putting things that aren't code in code tags, etc.), introduces new spelling mistakes, etc.
When rejecting these edits I'm left with two choices: Either check 'vandalism' (which in most of the cases isn't appropriate), or write a custom rejection reason. As this is by far my most common reason of selecting custom, I suggest that "changed the post to the worse" should be a separate option for rejecting a suggested edit.