Maybe I’m misunderstanding your suggestion, but shares are already treated as ordinary income when they vest (when the shares are released to you and you first gain the right to sell them).

If a company pays you $1M of shares, the IRS treats it exactly the same as if you were paid $1M of cash and you used it to buy the shares. The capital gains work the same too: you pay capital gains tax on the difference in value between when you receive the shares and when you sell them. That’s how it already works.