A 'starship simulator'? Is this the kind where you can run around inside the starship, or do you just get a pilot's view? How big is the starship? Will it have other crew members? Can you shoot or destroy other starships/bases/planets?
Let's see...
Accurate Einsteinian relativistic physics, portraying the realistic warping of the space-time continuum.
A computer which calls you Dave and refuses to let you do anything.
A Death Star style superlaser cannon.
Easy controls (easier than Frontier).
Automatic pilot for those complicated coincidental orbit calculations when trying to rendezvous with planets, and also landing.
Steam jets when landing.
Cup holders.
Swivelly chairs, especially for the captain.
Consoles which blow up showering sparks everywhere at the slightest hint of the ship being attacked.
Set the game ridiculously close in the future (i.e. 2004)
Once I was but the learner,
now, I am the Master.