Last night, I posted some thoughts on the new in game editor that I'm planning now. This topic is very much open for discussion. Since it's still in the design phase, now is the time to make suggestions.
One thing I've thought about a little more is that the options you have available should be based on the thing(s) you have selected. Everything will have a list of editor plugins that can be used on it. If you have a few things selected, only the plugins that work on all of them will be active. Selecting things is a bit more difficult. In the old version, you could select objects by clicking on them or by selecting them from a list. There had been no way to select an area or realm previously.
I'm thinking maybe a bar across the top of the screen could show the various services that were running and possibly allow you to select a connected server (the client can be connected to more than one server at a time). So you could select the Sim service and then it would give you options for selecting areas and objects by various means. Selecting the Realm service would give options for selecting realms.
Basically, the client will request the list of services that work with the editor, then when the user clicks on one of them, it will request the plugins associated with that service. It'll probably mean a standard api call that can be used on everything from services all the way down to bodies attached to objects.