Ive got a friend who is a die-hard FSU fan and watched every snap of EJ Manuel, and told me specifically a couple of months ago that he would rise because he would look great at the combine...
BUT..... would avoid taking him with a high draft pick. He never was able to have a consistent motion to go along with the footwork, and like you said, at times had a hard time reading his progressions and locked on to his primary wr too often.
But his measurables are insane, and Im sure with good coaching he could put it all together.
Would just be wary of drafting him with our early 2nd.