This point isn't necessarily to say AJ Styles is bad on the mic, but he's certainly not a great on it. His career has been built around ring skills, and in the early part of his career, his promos definitely did need work. He did mature into a more rounded performer with TNA, but you still wouldn't say he's a WWE standard when it comes to charisma. As for gimmick, he's not exactly as definable as a certain character, he's more used to just playing AJ Styles. That's where another danger comes in, WWE may choose to give him a new name, they may choose to give him a character gimmick. That could be a curse or a blessing, only time will tell. One thing for sure, he's going to have to adapt to the "entertainment" aspect of WWE.