Agreed. As many have said, Seth's post sounds like a terrible idea. Although there's no simple solution, an up-front equity split will have fewer potential problems down the road.

Whereas vesting is just linked with the passage of time, putting in milestones is very dangerous. It can lead to all sorts of erratic behavior, all in the name of achieving milestones, which may or may not be relevant. You can't just look into the future and know what the right goals will be.

VCs definitely include vesting schedules but tend to avoid milestones.