I don't think his trade value went up because of the Toffoli trade, but that his "perceived value" has gone up. NONE of us have any idea of what specific players trade values are. The talking heads like Friedman, Marek, Brooks etc also don't know what these players' trade values are either, they can only speculate. But if Tyler Toffoli is traded for higher than what his perceived value is, then it's logical to think that maybe Miller's perceived value is also higher. Or the Flames just overpaid for Toffoli because they really wanted him. Could be either.
Well, they might be told information as to a players value but that should automatically be dismissed because GMs sharing this information are doing so with purpose. So automatically, the motive of sharing information on value should be questioned. And that's if you even believe the source (eg Friedman, Dreger, Seravelli, Eklund, etc).
Keep in mind that a lot of the benchmarks being thrown around have been coming by deals from one team: TBL. If TBL is the only team willing to put such a premium on certain players and they're not involved, the price/ask/value either comes down or the player isn't traded if the remaining teams (not TBL) think it's too much. So this is a common thing that you see on HF that's problematic in determining value.
Secondly, if Calgary is a playoff team who is willing to trade a first for a forward, guess what happens when you lose one of the potential suitors for other forwards? By removing one of the potantial suitors, it becomes less competitive, which once again, would negatively impact the price/ask/value. I mean, the ask might stay the same or go up, but if no one is willing to pay that, then that's really not the value/price. The price/value is significantly impacted by what others are willing to pay.
Sorry if it's offensive that I explain this - I know it's kind of remedial. And a lot of people know all of this. But when you see the behavior and some of the comments, it should be reiterated.
One other thing: People keep citing what TBL has paid. But what about what Toronto paid for Foligno? Not all of these scenarios end well. You'd think GMs pay attention to the failures as well as the successes.