He's a pure pocket passer plain and simple. His mechanics are great .He's extremely accurate on short and intermediate passes. Just don't expect a rocket arm like a Haskins. He can under throw his deep balls. If he gets a pocket he can be dangerous. He's VERY smart. I said this before he was drafted. He was arguably the most pro ready QB going into that draft. One of the best things he does is he knows how to throw his WRs open. He can fit it in a tight window. He stands strong in the pocket and doesn't panic. He keeps his eyes downfield. He's mobile enough to elude pressure in the pocket, but don't expect him to outrun anybody. Overall, If we protect him, he could shine.
I think the attitude thing is overblown. My concerns are that he needs to read defenses better, but if he's smart that could be coached. His deep balls aren't the greatest. Some times he can play hero ball too much. He's not great on the run. He had durability concerns in college.
Basically Rosen struggles when he doesn't get a pocket like other QBs. If he is forced to be on the move, he's significantly worse. If he gets time, he's dangerous.