Not really sure if that's a memory breakdown or something similar. Anyway, ISS had him top10 in their preliminary rankings but mostly he was somewhere in the late 1st.
F.Ex. TSS (McKenzie) gave Drouin an HM and on the Hockey Writers' list he was down to #22.
http://thehockeywriters.com/preliminary-rankings-for-the-2013-nhl-entry-draft/
http://www2.tsn.ca/draftcentre/feature/?id=9600
Marner isn't the tallest but the height shouldn't be a problem. For him weight counts a little bit more and gaining lets say 20lb for someone with a very fragile frame isn't just a walk in the park and you reach a limit pretty fast. The tools Marner has, do not apply in the NHL in the way he dominates games in the OHL. He will need to be able to outwit guys that won't hesitate to use their size to nail you to the next wall or hit you on the open ice. The transition will be a lot harder versus someone who already can muscle in the corners on and off the puck. What comes to Strome, yeah he has skill but as was said the speed isn't there yet. 1st line center abilities alone doesn't warrant an edge on a potential elite two way winger. Tough to compare all three since Rantanen has been playing versus professionals for the past two years now while the two others have been on a scoring competition. Claiming it isn't even close is even more biased than saying he'd be ahead of the other two at this point.
Tarasenko and Kucherov come to mind as pretty good examples of wingers drafted low and becoming more or less indispensable pieces for their franchises.