[0]: http://appshopper.com/games/bejeweled
There are a number of workaround for this, and one is to upload the same game with slightly different title until you hit on the magic combination that gets you sales. It sucks to have worked hard on a game, and it fails because of the wrong combination of title and keywords.
I agree that that's likely the main idea, but there's real value in providing different themes. I like jewels more than I like candy art.
People that clone games lose. Always. They don't know what to do when there's nothing more to clone.
How are the games by PopCap not polished? It irritates me even more that King copies TWO games from the same company... They truly are the new Zynga.
Trade mark has the benefit of addressing names, i.e. word search in the App store.