Dividing up equity is an ugly issue, because sometimes it's more about availability of talent, contract clauses, time (4 years is not a lot of time). Best to get it right the first time.
Are you saying you think it makes sense to have vesting schedules longer than 4 years? I've seen "evergreen" clauses where employees constantly get new options, but not vesting schedules longer than 4 years.
I've spent 2 years as a founder at my start-up and it seams like a drop in the bucket. I was just able to turn around twice and all of a sudden, I'm 50% though my vesting period. But then the other founders are 50% or more though their vesting period as well.
It may well take 8 years to get this company to IPO. 4 years seams standard, but it feels awfully sort for some reason.