This is fine if your parameter listeners are only needed to update the UI, but if you need those callbacks for altering the processing in some other places of your plug-in, you’re going to have big issues during offline bounces/rendering of tracks.
Cakewalk SONAR, for one, completely grabs the message thread during those, and runs the rendering in another thread, so your callbacks will queue up until the end of the offline rendering, when serving them may be too late.
I think two sets of listeners may be needed, one for sync notifications and another for asynchronous ones, or the possibility to specify, when calling addListener(), whether the given listener should be notified synchronously on whatever thread, or possibly asynchronously on the message thread.
Something in that direction was proposed here: Async addition to ListenerList