Making micro-transactions more profitable would be an unfortunate course of action. There are enough of those apps in the store, and they are clearly profitable enough if they can buy Super Bowl airtime.
Subscriptions for apps should be different, but I see a challenge in drawing the line between Spotify/Netflix and a scam app like "awesome culculator" that charges $5/mo to people who don'didn't realize it was a subscription (there was an article on HN this week about apps like that, targeting kids and the elderly, of course).
If Apple has a stipulation about requiring a website, then maybe subscription-based apps can get a discount on the 30% fee if they also have a web or desktop-based version of their application that provides comparable functionality and takes payments.