I think changing the track to stereo is very easy in Cubase. Or you could send the track to a stereo group channel which would create additional complexity in the project.
What’s the real benefit of your requested solution ? Just your preferred way or anything else ?
I’d say that “explicit is better than implicit”. If you want a track to have stereo information and use plugins to generate those, make it a stereo track. Having a track be marked as mono, but “automagically” suddenly turn stereo due a post-fader plugin and some setting somewhere could be really confusing for a lot of users, imho it wouldn’t be good UX.
As someone that is trying as hard as possible to have a 1992 workflow…
Its Cubase. Add a stereo group channel and send your mono track to the stereo group channel. Put your stereo effects on the stereo group channel and your mono source channel stays unspoiled.
In an analog world… that is what you would be doing. The return from your stereo effect would be coming back in on a stereo return bus, not a mono bus.
Essentially, I’m wanting to replace the panner in Cubase to resemble analog console panner which is essentially where a mono channel becomes stereo, splitting the signal and inverting their gain structure so one signal or the other gets sent to the main bus Left Channel or Right Channel more.
Perhaps the suggestion would be better posed as giving us a more advanced panner in MixConsole that emulates console pan.
For example, Softube Console 1 has this in their Channel Strip.