[ccostes]

It's a nice idea, but I don't see how you can objectively measure the risk or value of individuals like that. For example, if a company spends 5 years treading water/pivoting before it takes off, how do determine how much of future profits an employee who joined and left in year 1 should get?

I agree that the current system is far from ideal (just read through the Ask HN post asking early employees how much they made from their startup's exit).

[ian0]

You can use vesting schedules to deal with the time component. Any measure of value is going to be difficult (it is under any scheme) but risk taken is a little easier. If I look at the companies I have been involved in there are very distinct phases during growth in terms of salary, prospects and job security.