A reply shows that in a 4-year hypergrowth scenario where the employees holds through the period, the $$ difference in outcome is $21.6M for 4-year vest vs $13M for 4X 1-year vest[1]. That effect is not as bad as I expected, and it's not like this scenario at all applies to Lyft or Stripe anymore.
As a prospective Stripe applicant, this change doesn't really dissuade me from applying. $200k salary/yr + $200k stock/yr for Senior is just fine without the potential stock growth.
1. https://twitter.com/devahaz/status/1386729419650179072