Saw the game last night on NHL Network and looked closely at how the rink fit in there. Yes, it's a basketball only configuration but this is different from that of Barclays. All available areas of seating are useable with I'm guessing good sightlines. That said, there is a reason why it's been so long since they played hockey in there - it's not a good long-term option. Perhaps it would be useable as a temporary for one or two years, but no more than that.
As for the market, it is small, and they would have entrenched competition from the NBA, but the same challenges for the NHL in Salt Lake will exist in Seattle when the NBA comes back to town here so I'm not sure that that's even a concern. I'd have to think that if the Miller's were interested and were able to find a few other folks locally to help cover the costs of a team, I'd have to think it'd be a doable proposition. They will need a new building (I'd propose expanding the building out in West Valley City that did host the 2002 Olympic tournament) but I suspect it would have success.
In total, I think that the Salt Lake market as a long-term option should be something the NHL can look at. At minimum, it's surprising to me why VGK doesn't look at placing their AHL team there. See how the AHL fares in that market then maybe there'd be something down the road.