I should clarify that it's Internet Explorer _on Metro_ that won't run Silverlight (as far as is known). And, in consequence, ARM tablets won't either (because there will be no desktop mode, just Metro).

On the other hand, the new XAML-based API will be a somewhat easy upgrade path from Silverlight app to native app.

No no no! Windows on ARM does have a desktop. But traditional x86[-64] compiled apps will obviously not work. The desktop does still exist though.

Thank you for the clarification. So current x86 desktop apps won't run, but some might be retargeted and they would work.

There will probably be a Metro Netflix app. I think that's the idea.