Details are trickling out about Windows Phone 7 series. No multitasking supports for apps, apps have to be installed through the Marketplace, and native applications are not permitted – everything has to be done through either XNA Game Studio or Silverlight. There will be some sort of option similar to Apple’s enterprise and ad hoc distribution. And, of course, the app certification process is going to be fast and transparent.
All said, this doesn’t sound like a big departure from the policies and engineering decisions that have gotten Apple so much criticism. It does appear, though, that they will be much better equipped than Android to avoid hardware fragmentation — they are requiring fairly specific hardware features, such as a common button set and graphics acceleration. They can provide hardware manufacturers with specific benchmarks in XNA and Silverlight to ensure that the phone meets performance expectations.