On this forum if Forsling became an NHL star, Benning would be praised for his keen eye for talent at the draft table for drafting him.
That's the spirit. Though I think you misrepresent, just a tad, the order of battle arrayed for each side in the great Benning divide.
A GM can draft his way out of multitude of sins and him nailing mid round picks with some consistency should count for something.
Here Forsling has to become a) bit more than an average replacement level D any club can pick up almost every year (e.g: Bartkowski), and b) close the difference, if any, Sutter has over Bonino in production, intangibles, performance of linemates, etc., for this to go into Benning's loss column.
Assigning value to D is, I think, pretty straightforward when not talking elite players. You're either a top 4, not a sporadic multiple injuries caused necessity, or your not in which case the value is small. Nickel & dime stuff, or mid-late round pick, which while cumulatively important, still need to be considered in context of overall club performance. A consideration with Gillis enjoyed for the longest time, I might add.