It is, but that players value is entirely different than it is now.
Tampa was in cap trouble, off-loading a guy who had a down year is something they wanted. So going into trade negotiations, Canucks came in from a position of strength. And they still paid a premium on him. You have to judge the value of a player at the time the trade was made, not post. The deal, at the time, was risky. With the way, the Canucks pro-scouting has been shoddy in the past and Benning's tendency to overpay for players he wants.
Now you can say, "Hey, what a gamble, it worked out!". Or you can say, "This was hitting on 16 and getting 21.". Both arguments can be considered.
I think you can make another argument in favor of Benning, saying, "Benning paid a premium because he wanted to get out ahead and not get into a bidding war.". I think that's a pretty valid argument.
Another point I want to add here is not to get tribalistic over this. This trade has worked out for the team, and Benning deserves credit for it. I don't think many Canucks fans are upset that Miller is on the team. Instead, they believe that Benning could have made a better deal considering the circumstances. Let's not turn this into something where the two sides (pro-Benning/anti-Benning) draw a line in the sand and yell at each other. There can be a conversation about the risk that was involved in this deal.
This isn't reddit where unpopular opinions get squashed.