Unless you require graded vesting schedules depending on the level of exec, the 10 year vesting schedule applied across any employees receiving stock options would be a terrible idea for the down the line employees (who also receive stock options or RSUs).
I'm not a C level exec, but I am a fairly high grade employee of a subsidiary of a 70,000 employee publicly traded company. Part of my comp. is stock option based, as well as some in RSUs. RSU's have better downside protection as no option strike price exists, at some date I am given the RSUs, or cash equivalent at whatever the share price is. The options of course have a strike price, and they are only worth something if the stock appreciates.
For the middle or senior business line manager, all of our vesting schedules are usually 3 or 4 years (depends on a number of irrelevant factors). My influence or impact on our parent company's bottom line is negligible at best. Our total revs are tens of millions, <1% of parent total revs. However, the level of LT comp I get is based on a blend of our business line performance combined with the parent's performance, the parent is about 80% of the blend. Our schedule is graded, ok fine, at 3 or 4 years (not cliff vested). No Fing way am I hanging around having 10, 20, 30, 50% target (of my comp) tied to a 10 year vesting schedule. I'd leave.
Incentive/Long Term Comp. has been a pendulum of formulas, everyone new one is the next best thing, until it isn't.