Why not?
This could probably already be done, but in addition, MIDI 2.0 is here, and accounts for needs of the micro-tonal music community of which many world traditional musics are.
Iam really looking foward into new feature in midi area :
-Midi Multi-client Access (grrr only loopMIDI as work-arround for years now) it would be so much easier for PC user, hope midi 2.0 will change that.
-Midi macro control
-and yes !! Microtonal goodies (for all vsti)
But i guess it’s not only up to Steinberg, it as to be on both side. I mean improvement have to be done also from third company to be compatible with this new MIDI 2.0.
Some vsti company include the possibility of editing microtuning setting and some are still not offering this possibility even not import .tun .scl files.
But yes a piano roll with micro tuning midi editing like Melodyne for the audio note editing, would be so dope !!!
Yes it would already work with Halion and Groove Agent 
+1
That would be useful. Of course there should be a way to snap tuning to a defined offset while also retaining the option to return to regular temperament.
Currently, micro tuner is not always dependable. Sometimes it works well, other times not so much.