Don't be silly. Are you really suggesting that Apple is doing this to clean up your news feed? They don't care whatsoever. Facebook does, you do, Apple doesn't.
What OP said is right. This is about Apple having tighter control over the app marketplace, not your news feed.
Fine, but preventing spammy behavior is still a good thing.
I don't see anything about restricting use of Adwords, eliminating the "direct to app store" URL infrastructure in Safari, or even telling you not to let users share your app with their friends via social media.
All Apple is doing is telling you that you can't incentivize (read: effectively require) users to do pollute their friends news feeds, which is already a distasteful spam tactic and socially unacceptable. Whatever the ulterior motives, this discourages bad behavior and is still better for users.
If "explicit permission" to post to my news feed is necessary to proceed through your game in a reasonable way, access features I want, etc... then yes.
When your "marketing channel" is my Facebook news feed, then yes, this is absolutely what should happen.