There's a possibility that you either get a better young defenseman (thereby winning the trade from an individual value sense, *and* aligning better with your core - a "synergy" of sorts), an equal value defenseman (but still creating value due to the synergy) or a slightly worse individual player, but still making up for the difference through that synergy.
In my previous analogy, the first two scenarios are trading the $2,500 bike for the $5,000 car and selling the car for $6,000 and/or buying the new bike for $2,000.
If you think re-purposing Miller to a younger forward is more likely to meet the mark from the individual player perspective, I'm all for that too. Maybe instead of Dunn you target Thomas from St. Louis. The point being that even if the player acquired doesn't have the same impact Miller has today, the cohesiveness with the core and future value (at a time when it will be most required) will generate further net value. You go from winning one trade that didn't make sense directionally to winning two, and aligning with your strategy.
I don't think they're anywhere close to contending, which is why I'd suggest re-purposing Miller. I just don't see the need to consider this a "bad" trade - 3 more "bad" trades like this and we'd accidentally become contenders.
If we're reducing it to one singular overarching mode, every GM in the league should have the mandate to contend for a Cup and maintain a competitive window for their entire tenure, which ideally spans decades. Guessing we'd both agree that is not a practical strategy at all as it is overly ambitious.
Your example is actually very demonstrative of what I'm getting at. By the same metrics used to assess the Miller trade, it was wrong for Wilson to acquire a 1st round pick for Toskala, vs a roster piece to help push them over the top for a Cup. As you said, it made no directional sense, but was simply a terrific value proposition for a mediocre goalie.
But if I was Wilson, from there, I'd have flipped that 1st for the player to get them over the top. Maybe that pick could've landed them Hossa in the offseason, and with him on SJ vs Pittsburgh the Sharks get past Detroit and take the Cup in 2008.
Of course, maybe a Hossa-like player was never available and the highest value proposition was making the pick, even given the limited likelihood of success. There is obviously a portion attributable to luck that vs an average 1st round pick (which was already surplus value for Toskala) they added way more surplus value by nailing the pick and landing Couture, who added value for years, not just as a one off like Hossa (a best case scenario) would have done.
Back to Toskala vs Miller - the only difference is that the "perceived" value of Toskala at the time was probably lower than a first, so the perception was that Wilson made out well (which he did). Miller was also "perceived" to be worth less than a 1st and a 3rd, but Tampa didn't make out so well, as Miller didn't flop like Toskala did in Toronto, and quite the opposite, is worth much more now.
