Where to begin... The entire store is set up badly.
1. Too few categories. Most consumers only look at the first screenful or two of apps in a category, so any new app gets at most a week of exposure. After that, you have to rely on users finding your app using the search mechanism.
2. The search mechanism sucks. I have seen horrible, horrible apps appearing on the first few screenfuls of search results, while newer better apps appear on page 10 or 14.
3. Unlike on Amazon, in the App store there is no way hold anyone accountable for their reviews-- no real-life name is given for instance unlike Amazon's mechanism. This lets other programmers with competing products put bad reviews in with complete anonymity, and obviously they have a self-interest to do so.
4. Unlike on Ebay and Amazon or any other website where items are sold, no response is possible when reviewers outright lie, as when someone says a feature is missing that is in plain sight. Nor can other users vote on reviews or respond to them.
In short, nice people who work hard to create useful apps and play by the rules are bound to get screwed in the App store, whereas ruthless types have many options open to them to prevail unfairly.
In addition I would add that another way in which the App store sucks is that apps for all languages appear in browsing and search results. If I mainly speak English, why would they be showing me apps in Chinese and Korean? Have I told them I speak Chinese? No. It's stupid. There isn't even a way to turn that off.