How about improving the score editor to work at the level of Sibelius or Notion including all the notation bells and whistles (MIDI CCs for more than just the sustain pedal, velocity, etc)? GPX imports?
Cakewalk has always been the premier MIDI tool, it would be nice to see it recapture that space.
 

Overture is notation program where is notation connected with midi. All notation signs / ornaments and expression maps have midi sends, keyswitches, prog. changes, velocity etc.. I think this is the way how to improve Score editor in Sonar.

Well, that may be a very good idea

We all know that the staff view will never be improved. I have raised the issue for decades and basically nothing is done. You can't even write 88 notes on a sonar staff (and if you think you don't need 88 notes then buy a construction kit toy like Ableton). So how about improving the way Sonar and Sibelius work together either through a "wizard" rewire connection program or the ability to export a Sibelius format file that can be imported into  Sibelius and easily rewired back to Sonar. 
And please no comments on Sonar is a DAW and not a notation program, for once in your life think outside the box.