wrt Coburn and Bogosian, I see them both as being 4-5 d-men and each are not quite the equal of d-men selected before or after them in their draft year. Similarly, wrt Gudbranson, he was the top d-men in his draft year (no one else selected before #10), and he's also in the 4-5 d-men sort of ranking-- that is, a bit of a miss for a d-men selected #3 overall (and is pretty much inferior to other d-men selected that high in their draft year).
wrt the d-men class of 2016, firstly no elite top class d-men (better than all his compatriots) and the top 3 are all rated below a group of up to 7 forwards. As for being compared to Hanifin, none of them are even chose. And I would suggest that Provorov is also a superior prospect to any of them as well. Werenski, well finally that's about the level that the top d-men class of 2016 are at. And W. was drafted at #8, which is about the measure of where these guys will begin to be selected this year. So, all 3 are a bit of a stretch to go #4 to the Oilers in terms of BPA. A debate as to whether Sergachev/ Juolevi/ or Chychrun are better prospects than the 2013 draft of #7 Nurse or #8 Ristolainen, now that's more of a close call, and it might be fairly argued that the 2016 d-men class is just a touch below N. and R.
wrt the 2012 draft, I'd put the 3 2016 guys in amongst #7 Dumba, #8 Pouliot, and #9 Trouba, with #5 Rielly and #6 Lindholm slightly higher (and #4 Reinhart was a draft mis step). wrt the 2009 draft, I know #2 Hedman was slated to be a potential superstar, and #6 Ekman-Larsson, I don't know remember much hype about him, but ... he's become the value of a top #3 or better draft pick.
and wrt the 2008 draft, it was a year in which the top 3 d-men were significant prizes to behold, and all were supposed to achieve a level higher than that forecast for the top 3 d-men of 2016, who sort of more approximate the #5 pick Schenn.