Platform Developer Creativity
Any platform that opens itself to 3rd party developers to develop software for requires that these developers be creative. Without creativity the software that will be written for the platform will not promote it. The platform will be viewed as second rate or not leading edge. The quality of the software will end up being second-rate and the platform will end up being viewed as same.
What does it take to promote creativity. Well, that's pretty subjective. But, it's easy to detect what hinders creativity. Development tools and methodology restrictions hinders creativity. When a developer is unable to pick whatever programming language makes them the most productive and allows them do to what they want to do, or program how they want to program; they're creativity is hindered. When they're unable to use translation layers or compatibility layers, they're creativity is hindered.
And what are the consequences of restricting creativity? Well, the end-users suffer. The platform doesn't get the applications the community really wants, it stagnates, and becomes second rate.
It's one thing to only provide development tools that support a subset programming languages or language; but it's another to actually restrict what language developers can develop in. It serves no purpose other than to control.