I'm sure that I've asked before but I can't find it.
I do recall an answer like it will be in conflict with the built-in editor of wpForo.
So I tried.
I installed TinyMCE Advanced editor.
It looks like they can live in harmony and the system did not crashed.
TinyMCE Advanced added features appears as drop-down menu, not all features where shown.
But there is some mingling...
So, I think that it will be a good idea for the future to implement support for other plug-in editor and perhaps to limit to compatibility to few popular.