Not sure he's wrong. Part of refining his game will no doubt be improving and incorporating other moves to keep upping his game. He already does have some other moves. He needs to elevate those moves, but it's not like he only bull rushes. He has an uber elite bull rush for a rookie and some other not so elite moves. AD didn't always use either three moves or the bull rush. He had other moves when he was getting stale mated. I'm sure Verse will do the same.
I think his greatest improvement will be in closing the deal at a better rate. I would put a higher priority on that than new moves. Hopefully he can do both, even though he didn't really have to in college.