The Mac App Store is a thorn in the side of basically everyone. The promise was that it would be kind of like the iOS app store and you'd have a one-stop shop to find the things that you want. Installation would be easy-peasy, and you'd get Apple's famous quality control as part of the deal, etc., etc.
The store just makes things worse. The apps are significantly restricted in their ability in the name of safety, so whole categories of applications won't ever be found there (Little Snitch, for instance). The store is as hard to search as the iOS counterpart, so you're just as likely to search on google for an app as the app store. The whole system reeks of neglect. The whole thing feels like a letdown whether you're a developer or a user.
So are scams a surprise? Not really. The store just feels like work that Apple felt that it HAD to do, rather than something that they were excited to do. As a Mac user and general Apple proponent, I really think the Mac App Store is an embarrassment. Either put some time and money and people into it, or shut it down.