I remember an interview with Marner after the Mem. Cup where he said he ws close to 170lbs. That's 8lbs more than what he's listed on hockeydb. There's a solid list of top end players that never went above 180lbs in their careers and I think they did okay. Datsyuk, Gilmour, Kane to name but 3, Ehlers is also 172lbs.
If he wasn't a Leaf, his size would not be front page news every other day.