I don't know if he's consistent, but there's video out there of Haener throwing dimes on deep sideline and corner routes.
When the QB is accurate, at least 1 receiver is always open, and Haener seems accurate with all the throws. You can't teach accuracy, but everything else is teachable.
He has a lightning-fast release and seems to be a fast processor. I've seen him doing the Joey Burrow thing where he's running for his life then accurately throwing to someone who flashed open down the sideline
Don't know if he can transition, but he has 2-3 very good NFL tools to work with. I have a feeling he has been obsessively studying the Pro game for years, and nothing in the NFL will take him by surprise. I think he will make pre-season a little more fun than usual.