NFL: What if teams were allowed to trade regular season wins?

Good point, perhaps the league can put a cap on how many wins can be added to a season, maybe 4?

Now that you mention it, this idea does seem more suited for the MLB where the big city teams with the large payrolls are well-positioned to lure stars away from smaller markets.

This is true, and ideally this type of trade should only be allowed in the offseason (so it can’t affect the results of an ongoing season), and wins cannot be taken away from previously completed seasons, only future seasons.