I think that's where you're wrong. DeShaun Watson is pocket passer WITH the ability to run. There's a difference. You don't put up 400 yards passing on Alabama if you're strictly a read option QB. Remember, he did it without his best receiver Williams who was suspended last year. Watson runs because he's forced to with a bad OL, plus with the read option incorporated, it makes the defense put an extra defender on him. I would compare him to Russell Wilson and Jameis Winston in that sense. Those guys can run the ball, and they do on occassion, but they're also outstanding passers.
Watson was making NFL level throws as a true freshmen...while Trubisky was riding the pine at UNC behind Marquis Williams. The one thing I'm concerned with Watson is his propensity to throw INTs. Other than that, IMO, there's at least a 2 round gap between Trubisky and Watson. Whoever drafts Trubisky in the first round is going to regret IMO.