As an instrument pilot I would like to see more facility for accurate instrument behaviours and approaches. Particularly a more accurate Flight Management Computer fully interacting with the Autopilot, that can enable all categories of approaches including Autoland.
A tutor that actually instructs according to the proper aircraft checklist.
Microsoft should Negotiate with Jeppesen to have a database of airport approach plates, SIDS and STARS for at least the major airport hubs in each country. This would be a start.
I would be happy just to be able to file and fly a SID or STAR and use my own plates. The most annoying thing is being 80 nm from the airport and getting vectors.
The only way to fly the STAR is ignore ATC.