[EDIT]: I misread the bill, ignore this comment :)

So, the devil here is in the details: https://www.congress.gov/bill/114th-congress/house-bill/5719

The tax bill will come due when the employee leaves the company; so this doesn't really help a lot.

Has a few caveats that make it inapplicable to early employees too.

Interestingly, it seems like it applies to stock, not just options, which if it didn't come due when you left the company, would be great since it would mean that startups could stop dicking around with options for tax reasons and just issue RSUs.