I dont know if I support your suggestion or not. It has its reasoning I have to admit. But I believe overall there are easier ways to prevent to oppose slow players. Such as not joining 9d boot games.

If you use up your whole banked time in first turn thats your own fault. Just dont play that slow and you won't use it up. (I argument with your own arguments (I couldnt resist)

But what if only one player plays slow ? What if in a 3 day/turn tournament this player never uses the commit orders button, but instead just gives his orders in and lets the game auto commit once the 3 days are up ? What if he does that every single game of every tournament he plays in ? Is that still ok ?

Yes