I think of it this way: let's say I bought an arm windows 8 tablet. Neat! And it was only $200 with a 4g contract. The battery lasts all day, just like the iPad. Sweet! But, its not that powerful, so i want to make sure the CPU isn't getting bogged down by who knows what running in the background. And my 4g plan costs a lot if i go over 4gigs, so i need control over my data use at all times. Also, 95% of the time, I'm not going to have a mouse or keyboard, and this is the economy model, so the screen is only 1024x768, and the screen is small - just 7 and some inches.
Now, remember that pretty much all win32/wpf/winforms apps are designed for high power x86 pcs connected to landline internet plans with 100gb or higher limits. And, given the choice of just recompiling their existing app, or rewriting it to be touch and power friendly, and to resize properly in very small screen sizes, most devs would just recompile and call it good, despite the fact that it drains my battery, sucks down data like it was free, and only half the UI actually fits on my screen. Oh, and it installs a service that makes every other app run slow.
Do you still want win32 devs to be allowed to port their apps to arm? Because I don't. Why I NEED, are desktop-style winrt applications. Applications which I can install from the windows store or from a private corporate app list. Apps that use a UI framework designed for low power, touch enabled devices, but can take advantage of keyboard and mouse, when i need them. Apps that list all the capabilities they use, that adapt to small screen sizes, and that i can uninstall with a couple of gestures.