Cole was mentioned as a potential high first rounder entering his senior season, but as the season went on he slid a bit. Id say he was probably the 4th best HS arm in last years draft, after Taillon, Whitson, and Covey. Still HIGHLY regarded, but he wasn't a true elite prospect.
I suppose in the end he does have #1 potential, but so does anyone with a power arm. There's probably 25 pitchers in this draft that people label potential #1's. I think realistically, there are only a handful of true aces. I guess it comes down to your opinion of an ace.
I think of Felix, Lincecum, Halladay, guys of that ilk. Some might consider Matt Cain an ace. He could be a good #1 on most teams - I wouldn't say a true ace though. So maybe Im a bit more strict on a #1/ace. I definitely think Strasburg has that. I think Purke has that, if healthy. Zimmermann is awesome, but I don't think he's a true ace. I think Ray, Cole, and Meyer could be up there with a Zimmermann type ceiling, but I wouldn't put them near a Strasburg.