When you hire 12 baristas are they competing to make the most coffees or is their job to handle customer's orders? If their job isn't to compete with each other then don't stack rank them. Use other metrics like #of incorrect orders or w/e and decide what you think they should've done and if they did more than that give them a bonus. If they do less then maybe you need a new employee.
> Microsoft always suffered from rewarding egotists and political animals over people who did actual work.
That has nothing to do with grading on a curve. You can assign people to the top of a curve based on "egotist" criteria or based on "work". Nothing about a curve or stack ranking requires it to be based on "real work".