I've been doing some thinking. To be able to cross BLG and RTB, RTB will function as normal, just there will be addition options. There will be a separate friends list for BLG friends. You'll only be able to group chat and create chatrooms with other BLG users of course. They will somehow be marked differently. If they're marked as an RTB friend, they will not automatically be added to the BLG list. The requirements to create a chatroom is undecided, but if it goes unused for a long period of time, then it will be deleted. If you take RTB away, it automatically puts you in the BLG General Discussion instead, and it uses BLG's own chat screens. If I ever decide to make a wrapper for the client, voice chat is a possibility.
I've also been thinking of implementing an add-on manager for the server side. If RTB is installed, it checks for possible add-on updates, then sends a notification to the client. The client can go in an update their server remotely. I also want to make notifications more of a thing, so important notifications (aka anything not relating to dynamics such as chat/friends) will stay in your notification log. Stuff such as error reports from your server, available updates, or messages from an add-on on your server will is considered important. Alone, each instance of Blockland is it's own beast that only connects to your other instances via your key. I want to unify the account, and make things a lot more fluid and user friendly.
As the wrapper isn't getting much progress done, I may start working on this stuff (originally BLG3) and pick a point where I want to release. Whatever isn't ready at that point is pulled from the release.