Sports in general are in the dark ages when it comes to using technology to streamline, verify, and interpret live play. You can easily come up with 5 things the NHL could be using already in a couple minutes.
That said, the NHL does a better job of implementing new technologies than most leagues. Most of the time sports takes the cautious option and does nothing or waits for someone else to do it first. The NHL is already using centralized review (with on ice primary decision taking into account when inconclusive) and most other sports are using TVs in the same stadium on a closed circuit network.