The complicated answer: WPA
An important clutch statistic that has gained prominence recently is Win Probability Added (WPA). This stat calculates how much a player’s performance truly affected a ball game. For example, a strikeout with bases loaded in the ninth inning of a 4-4 ballgame would be significantly more important to the outcome of the game than a pop-out in the eighth in a 10-0 ballgame. The strikeout would produce a much higher WPA than the popout.
So fixing the issue with pitching wins with this is simple: give the win to the pitcher with the highest WPA of a game after their team takes the lead.
For our earlier examples, Daniel Bard, Mike Muñoz, Player B in the third scenario, and Player C in the fourth scenario would all get the wins, as their WPA was the highest of any pitcher after the lead was taken. This would be the most certain way to ensure that the pitcher that deserves the win the most gets the win.
The only wrinkle in this idea is that it would heavily favor closers as they are commonly thrown into high leverage situations and would benefit from having two innings where they could receive a win, whereas most relief pitchers would only have one.
I highly doubt that MLB will change the way wins are awarded anytime soon. It is a flawed system that could easily be improved, especially with the DH in place and the Ohtani Rule in effect. There is no longer a reason to keep the system as it stands. Colorado’s first win of the season showed why that was the case.
Note: Data for this article was provided by Baseball-Reference