I am not sure how exactly this island-tier thing works, but it might be less suitable for multiplayer than usual.
If the main goal is to beat the island, then what will do newcomers when all low-tier islands has been opened and wiped from resources?
And for the server with harsh PvP rules, like the snapshot - how newcomers will hide from PVP against established players?
Spawn/road camping might be an issue when land area is small and all routes via portals are limited and can be easily controlled.
Anyway worth trying ofc. For science! (yes, finally finished Portal 2 recently
)