I don't think gambling on Merkley is gambling on a low-IQ guy figuring it out. You are betting on a troubled kid to finally get it, and then rapidly makeup on lost time. Which is why I wouldn't have drafted him. I just don't really see him as an example of gambling on low-IQ. To be honest, the only position you can really gamble on lower IQ guys is very toolsy power-wingers, although, a lot of those guys naturally get over-drafted before the value kicks in. Guys like Chad Kilger and Virtanen. Useful bottom-6 guys, but absolutely lost at the top of the line-up because plays die on their stick. Evander Kane is by far the best example of this type of player who has gone on to find some level of success.
Power wingers (or anyone who can physically dominate against smaller competition) are a good example. Offensive defensemen are another good example. They can get away with their mistakes and taking more risks because the competition is not skilled enough to capitalize them as often. Really it goes for anyone, because you could have more skill than your peers, or be faster than your peers, but as soon as you get with the best of the best, you do not differentiate yourself as much. Your only chance is to have the IQ and desire to be able to develop, grow and adapt your game constantly, and to be able to recognize the few chances you have to make plays so you can capitalize on them. That IQ or vision (or whatever you care to call it) is something I believe you either have by the time you are drafted, or you don't.
Even guys like Virtanen or Kilger. Maybe they don't have the IQ to match their top 6 skills, so don't take them high up in the draft, but they still have the IQ to stick in a bottom 6. You still need to "think the game" at a certain level (i.e. know where to be and which plays to make), even if it is in those kinds of roles. Otherwise, they won't even be able to stick in a bottom 6 role, regardless of their skill level (just ask Yakupov or any number of the other top 10 busts throughout the years with immense skill). Even when they were drafted, they probably said that there were red flags for their IQ which would limit their ability to match their skill, but not so much so that they would never make the NHL... Otherwise they never would have made the NHL.