Jackman's plus-minus is -11 on a team with a net positive plus-minus total. Berehowsky's is -16 on one of the worst teams in the league. I'd hazard to say that Berehowsky's a far more polished defenseman that Jackman, at this point.
If Jack could skate and pass, rather than just possessing the ability, why wasn't he developing on the ice? He's played plenty over the last few years. He may turn into something, but I doubt it was going to be this year, with or without lots of ice time.
Berehowsky's played plenty over the last few years, too. He's not a huge physical presence, and never has been, but I wouldn't go so far as to say he's afraid of damaging his knee.
The comparison with Dempsey fails because Nathan proved himself at an NHL level. Quinn, for some reason, couldn't get his mind around such a smallish defenseman, and we lost a reasonable player.
Honestly, what's the problem here?? ......