The iOS 6 app store is less dynamic than other prior app store iterations. Example being I have an app listed as number 19 under a particular search. I've been checking that search every day and we are always 19 on the list. No change whatsoever even though our downloads have fluctuated in that time. Why are we 19? No idea. Before it meant we had less downloads than the people before us. Now I have no idea. It remind…
Also, in the previous system you could've positioned for a term completely unrelated to your app (e.g. you have a weight tracker, and you position for celebrity phrases because they're more popular). My guess is they try to stop that.
Oh, and even in the past it wasn't just popularity that guided the results. We did a detailed analysis of this ( techcrunch.com/2012/03/12/appcod-es-launches-app-store-prediction-tool-tells-developers-which-keywords-work/ )