I know exactly what you are talking about Alan. Like you, I use my Yamaha MOX6 to write songs using at least 8 of the available 16 tracks in the MOX, then transfer the midi to Sonar for easier editing. You have the Tyros Instrument Definitions already loaded into Sonar, so you can change instrument sounds from within Sonar and then, depending on which new instrument you choose, change parameters of that instrument (velocity, duration, note position etc) to suit your needs. I do the exact same thing here, with the possible exception that my MOX is on the other side of the stage, so I use a Roland A-800 Pro midi keyboard to play the MOX. As far as the staff view...no improvements should be expected ever, as Cakewalk has mentioned before that programs like Sibelius do the job sooooo much better.
With that in mind...and I have not tried this, even though I have Sibelius 7 First...might it be possible to to open up Sibelius as a Rewire device and use both simultaneously that way?