It has nothing to do with Benning. It has to do with a perennial lottery team trading first round picks. It rarely if ever contributes to real team success. Also, the 1st round pick could easily be a lottery selection. Like I said already, the Canucks are barely a playoff team right now, and that's with JT Miller playing out of his mind. It's not unforeseeable that they miss both years, either way, it's a 1st round pick getting traded by a lottery team.
Yes if the Canucks miss the playoffs the next two years it would be an extreme team failure, that's the point. They're barely mediocre now, have major cap commitments beyond this year (any Hughes/Pettersson bonuses eat up next years cap already) and have big holes on the roster to fill or extend with Markstrom and Tanev UFA's. Plus these are the likely the easiest years of cap to manage as Hughes and Pettersson are still on their ELC's.
JT Miller can be a good player, and the price could be justified, and the timing for the organization could still be wrong. These thoughts can co-exist.
I'd say the Canucks need to make the playoffs either 3 of the 4 years of JT Miller's deal or at have a run of playoff success (multiple trips to the 2nd round or a trip to the conference final) for this trade to be justified. Hopefully it is, but 30 games in isn't enough to judge.