I feel like the minimum price of purchase proportional to the value of contiguous tiles so that vandalism can be mitigated. The most valuable investment people are making initially is with their time so that should be encouraged.
It would be nice to have a sort of wayback mode too so you can see all art that hasn't been modded away.
Looks like wplace.live. But you can get 256 pixels an hour, instead of 60 and ownership of tiles is permanent. Cool idea. Do you really expect a lot of people to pay for tiles?
The problem is the world is too big. If you could get a rough fix on where your user is and start with a focus on their local area you might get some engagement. Allow just how big it is to be something they might discover.
This is one of the major issues that made the reddit variant a rather big nightmare for mods.
It would be nice to have a sort of wayback mode too so you can see all art that hasn't been modded away.
This would be cool if it was free and everyone could just draw.. There are plenty sites like that atm tho.