Yea. It was a stretch to say it could be hacked. But keep in mind, it takes more than 10 minutes to build a new hack to a new OS. It only takes a brief time to get infected by an existing hack on an existing OS.
Also, limiting apps to an app store probably means only those 'new' windows 8/10 style apps will work on the OS and worse, it creates a closed ecosystem like IOS, Google Play etc, where it won't be long that Microsoft demands a 20% cut on all software revenues. I don't think we really want that. That's why Xbox and Playstation games always cost more than their PC Counterpart