Could also lump all x players into this. Would be neat to see how the game play differs from players with no restrictions and players with restrictions.

Not finding this an exciting thing. Admins aren't announcing who is sanctioned or not. So adding a board and then people guessing if someone is there for all x or sanctioned seems like hunting the red october.
I feel like I can also see that turning into another board of hatred.

I don't see why we need to encourage people to get sanctioned this way. However, for pedagogical reasons I think the list of sanctioned players should be public. It helps everyone understand what behaviors is deemed unacceptable and it also encourages those hit by those people to keep playing as they are less likely to be the victim of such plays again next set.

An all-X leaderboard is already planned for Express and possibly other servers.

We aren't going to add a leaderboard for sanctioned players because that could be viewed as incentive to become sanctioned. It's the same reason the countries aren't identified ingame.

By chance is there a way to allow them to landgrab bots so they can at least compete?
If not I see the numbers going down even more on players willing to play on solo servers. I dont see this as a gain but you might have more insight.

The ideal number of players to be forced to put sanctions on is 0. Seems unworth to spend so much coding time on so few players when a lot of other aspects of the game including the bots can use improvements.

I'll agree with this line all day long.

A leaderboard for sanctioned players would be rewarding bad behavior. All-x leaderboard on the other hand does make sense.
I could also see the case for allowing sanctioned players to still grab bots.