This will basically cause island wars. Imagine two players living happily on their own island, when suddenly they quarrel and even have a little chat fight. Since both of them have equal rights, this means that both of them are owners of all island property. Both of them won't want to leave the island as well. Of course, the idea is great, but getting it implemented will cause more evil than good. No support.
/coop promote sounds really good. This will promote people to play cooperatively and won't have to fear losing there blocks, time, and hard work. Multiple island owners can use trust, coop, kick, unlock, and lock equally and would be completely beneficial if you ask me.
I would love it if other players in a coop would be able to use the /trust command besides the leader.
