I would need to know what his neck situation actually is. I have no idea. I don't think he has a serious concussion issue based on what he's saying. I don't know there either, but I'm more confident.
WWE cleared him from the neck thing and didn't clear Edge, so it's obviously OK enough.
If he changes his move-set I won't be angry, but I don't like when fans assume guys should do X or Y based on their guesses of what's wrong with someone. If he does return and doesn't change his style, there will be fans MAD at him despite having no idea about his actual medical situation.