There is no measure which distinguishes one winning move from another, other than perhaps number of moves (which is only important if that number could cause a draw). Winning is winning.
To define a score which differentiates winning moves, we would need an off-board metric. Consider: if someone is actively trying to practice knight and bishop end games, this may be a very good move. However, if one is trying to make the game shorter (which is a very typical metric, even if there is no draw in sight), it could be a poor choice compared to promoting to a queen.
However, if I may draw from some non-chess history, I'd recommend a term from the story of Mel. Mel was a software developer in the age of drum memory. Drum memory was a fascinating beast because all of the data was stored on a rotating drum that rotated at a very predicable rate. If you knew how long your instruction would take, you could make sure that the next instruction's memory was right underneath the read-head when it was needed.
Mel was known for doing delay loops where he would intentionally place the next instruction so that it just barely passed the head before it was needed. Then the drum would have to do a full circle before reading the memory. There were optimizers which would place the memory in the optimum place, but he sought the opposite.
His term: it was the most pessimum location.
I think that if you called this move "the most pessimum winning move," you would at least get a few smiles when you explained it!