Maybe would be a good alternative for early power? Or the rush?
Neitehr would be viable options following your change. Ghostblade isn't an acceptable option even if you want early power, but you shouldn't want that kind of early power because you'll still be weak until you get to a certain BT has a similar problem. It keeps the ADC alive, but they'll still do very little damage. There's no value in the ADC staying alive to do no damage. IE comes first because it hurts more, and it will continue to come first until it doesn't. Back when BT hurt more, it was bought first. When IE started to hurt more, it came first. You can't change that with this small a nerf.
If you want more variety, there has to either be item reworks, or major balance shifts to make certain AD carries significantly stronger early in the game. Outside of that, you're not going to see
The thing I wonder about is if that would help bully laners to be relevant longer into the game,
Realistically, probably not. You'll still get outscaled at exactly the same item threshold, and even though your opponent is slightly weaker until that threshold, you're also slightly weaker until that threshold. Even though there is technically a difference in how it affects early game AD carries and late game AD carries, that difference is so minor that there wouldn't be any appreciable shift in their relative power. Jinx and Trist would still be the best AD carries.
If we need to nerf Jinx and Trist, we can just nerf Jinx and Trist. No need to make every other ADC suffer just because they're too strong.