This idea crossed my mind in a live situation as I was trying to figure out which VST Instrument was playing a sound which I wanted to modify the filter on, without triggering notes to find it by listening:
What if there was an option to make the instrument in the Instrument List flash subtle when an instrument is triggered - for example on a note-ons. The benefit would be that you would have a more graphical feedback of which instruments are triggered at the moment.
This feature could also be extended so that you can see which sample are triggered in the Sample List (beneat he Instrument List - if you’re positioned on a Instrument with multiple samples).
Another variation of this idea is to add a graphical MIDI-led on the VST-instrument view to see when it is sent or recieving MIDI. I think FL Studio has this feature.