Metaphorically speaking, I think every app store has slider in its settings panel, with "lots of crappy/derivative apps" at one end, and "subjective/random curation" at the other. You can't decrease one without increasing the other.

Of course Google leaves their slider pushed to zero curation, treating apps like web pages (index them all and bury the crappy ones low in search results). But Apple seems to like their slider in the middle, which is why it seems so random to developers. After all, even when applied consistently, subjective rules appear random once you modulo by the difference between the observer's and the reviewers subjective viewpoints.

Personally I much prefer the Google approach, but then that's probably because I'd like for app stores to become commoditized. Apple probably doesn't agree. ;) Their slider does seem to have moved over the past few years though - perhaps it's post-Jobs drift; perhaps pressure from Google?