I believe the “Ultrawide issue” could simply be adressed by adding a button in the lobby, when creating a new game. Just like the “item spacing” button that allows people to use their controllers, a similar button for “aspect ratio” would let players use their ultrawide gaming monitors.
This would let PVP players with 16:9 monitors disable that advantage in their “competitive” games.
I think it’s easier for Blizzard to implement this one button, compared to changing the game by adding features, such as fog of war or messing with the games core mechanics.
The game supported ultrawide resolutions in the Alpha so most work is already done.
I beleive that this is a solution that would work for most of us, if not everyone. People who want to play with ultrawide can join games that are not restricted and people who want PVP can rest assured that their games are restricted. And you can also PVP with Ultrawide if you join games that support that.