Hi,
I think that duplicate instrument properties is a waste of space for other thinks
(instrument global volume, pitch, scale, quantization, mono, hold)
If you don’t want to see those, then just hide them:

You’re right vV. I also really like this feature a lot.
But I think the lay-out could be better.
If the sampler/plugin/midi tabs were moved to the new instrument properties. you have all the instrument related stuff in the same area.
the button to open the instrument editor should be there as well. will function like a sort of more/advanced edit button this way.
But, the whole idea is to provide those options when you are NOT in the instrument editor.
Also, remember that the right panel (disk browser, etc.) aren’t always visible…
I’m all +1 for looking critically at the current solution, that it is a compromise doesn’t mean it cannot be improved in various ways.