Windows 10 did fix a lot of issues with old games for me, too. I couldn't play Morrowind under win 8, as I had no mouse cursor, but the "upgrade" to win 10 fixed that.
However, win 10 introduced so many system tasks that keep running in the background, grabbing all the CPU at the worst possible times, that many games suffered performance issues. I gave up using that machine for games.
Windows 10 did fix a lot of issues with old games for me, too. I couldn't play Morrowind under win 8, as I had no mouse cursor, but the "upgrade" to win 10 fixed that.
However, win 10 introduced so many system tasks that keep running in the background, grabbing all the CPU at the worst possible times, that many games suffered performance issues. I gave up using that machine for games.