^ That's not the complete story. Universal apps are only as universal as devs want them to be. Although a universal app may technically run on desktops, tablets and phones, it will still require some additional work for the app to present an acceptable UI on each form factor. Nobody will force devs to do that work, so such an app may still only run on phones.
I suspect this feature request is asking MS to allow even those apps specifically and intentionally restricted to phones (incl. non-universal phone apps) to run on other devices, using the phone UI and perhaps in a fixed size window.
I understand this desire. I just think the phone UI on a larger screen or non-touch device would make for a very poor UX.
Considering we're now so close to W10, I'd say MS would do better to ignore this particular request and let universal apps partially solve it when W10 is released.
That means not all phone apps would run on larger devices, but those that do will at least always provide an acceptable UX.