the very first assumption of this post is fragile "Although Apple doesn’t make these numbers public, I bet most people search instead of browse through the App Store categories to find the apps they’re looking for"
1. This is really far from certain. actually the reality is that most apps who get massive downloads from the app store got featured or from the top charts when they reach the top 1. I never heard a developer who had massive growth because he was "searched"
2. The App store has been redesigned mostly for visual discovery and not search. Explaining the streams, big stickers, card browsing
If you want to be discovered in massive volume in the app store the only way is to get promoted or top ranked
The other cases are edge cases and frankly do not justify complaining about how such results are displayed.
I'm pretty sure that when it comes to apps linked to a well known brand (e.g. Picasa, Twitter, Flickr) or solve some kind of specific problem (todo, email, finances) do have downloads primarily from search.
Discovery by being promoted or top ranked only works for apps where downloads are impulse-driven, games being the primary example. Searches on the other hand are intent driven, initiated by users that want to get something done. And I don't think developers of such utility apps want massive downloads, they just want to make a profit.
Also your argument about discovery needing top ranking is circular. To get top ranking you first need discovery. This is where iTunes fails its customers - as it focuses on the new and the shinny, creating an environment where apps that build a reputation slowly have no place, which is why most apps in the app store are released in a fire and forget fashion.
If you want to be discovered in massive volume in the app store the only way is to get promoted or top ranked
The other cases are edge cases and frankly do not justify complaining about how such results are displayed.
Ouriel appsfire.com