A subscription model would definitely benefit specific types of apps (we make games and are excited at this possibility).

The easy money's already been made in the App Store; with a million+ apps it's a visibility issue. No amount of changes to the App Store will remove the problem of there being a dozen apps that already solve the problem that your app solves.

That said, a subscription model with a reduced cut could improve monetization prospects for a lot of developers, indie especially.