Also look at the forwards that went immeiately after these guys. Its not like these dmen were taken ahead of multiple great forward prospects. Dmen generally go where they should in the draft. The guys drafted very high, like Doughty, Ekblad, Hedman, etc, generally DESERVE to go ahead of the forwards they went ahead of (e.g. Filatov, Reinhart, Duchene, etc). Similarly, the dmen listed above, genereally deserved to go ahead or at a comparable spot to most if not all of the forwards that went immediately after them.
After JJ -Pouliot, Brule, and Skille. So a pile of garbage. JJ may be disappointing, but aside from Price, he's still the best guy available at 3rd OA in that draft.
After Hickey - Gagner, Voracek, and Hamill. Again, pretty mixed bag here. One depth forward, one top line winger, and one bust. Hickey isnt exactly sticking out as a bad pick compared to those forwards, only compared to Voracek. But you could have missed just as easily by taking Gagner. Plus Alzner went right after Hickey (while also being consistently ranked higher) and he's easily better than 2/3 of those forwards as well.
After Bogosian/Schenn - Filatov, Wilson, and Boedker. A big bust forward, then two decent 2nd/3rd line tweeners, but its not like any stud forwards went in this range.
After Gudbranson - Johansen, Niderreiter, and Connolly. Johansen is clearly better, but as a group, the forwards arent clearly a step above the dman available here. Id take 1/3 of these forwards ahead of Gudbranson with hindsight.
After Larsson - Strome, Zbad, and Scheifele. This group is a bit better, no clear busts. But also no clear franchise guys either. I wouldnt necessarily take Larsson ahead of these guys in hindsight, but its not like the gap is big either.
After Reinhart - Forsberg, Grigorenko, and Faksa. One really good looking forward, then two meh guys. And keep in mind that the top 10 of this draft included Rielly, Murray, Lindholm, Trouba, and Dumba. So while Reinhart may be trending towards bust territory, you still had better odds with the 4th OA pick taking a dman than taking a forward.