Logic and most other DAWs are great examples of how instrument tracks can be used for multitimbral instruments without having a separate MIDI track in addition to each separate audio output track from the VSTi (the main VSTi output of an instrument track does this perfectly in Nuendo, but every additional output you add needs a separate MIDI track, which negates all copying/moving of automation parameters with the MIDI events for them and requires two new tracks - one with audio and one with MIDI - per VSTi output after the main, instead of just one). Combine the two like Logic and other DAWS do and you have a system that is fast, modern, and improves workflow by a gazillion.
The way this all works in Nuendo at this time is inefficient and clunky, and it should be modernized and made more efficient/fast. There would be no downside and lots of improvement. If for some reason you still wanted a separate MIDI track you could still make one, so again - no downside, only lots of upsides.
In big scoring templates I can’t begin to tell you how much of a significant improvement/timesaver/workflow improvement/session size improvement this would be. I look forward to having it in Nuendo!