Umm... Patrick Kane scored 62 goals and 145 points in 58 games in the OHL during his draft year. Please, tell me which prospect in this draft is comparable to that?
Drouin was literally outside the top 5 going into this year. Heck, he was 10th in the first ISS rankings of the year. To say he's going to make a significant contribution in his first year is absolutely silly, as is saying he's a guaranteed star. He has a ton of potential, but worth trading away multiple assets for? Absolutely not. I'd be happy to take him or MacK with our pick if Jones is off the board, but trading Couturier++ for him? Heck no.
How is this relevant to his future success? The kid was playing AAA hockey a few months before the rankings came out. No one had a chance to really see him perform and people credited most of his success to MacKinnon when that just wasn't the case. It's not where you start it's where you finish.