First, lets be clear, PCs, MACs and Linux machines run on similar hardware. So the ability to do this is a lot simpler. So from a logical stand point it makes sense. Though I think most people would prefer not to run VMware. Not sure about Chromebooks in all this.
Phones and tablets run in similar hardware too, OEMs will use the same hardware for Android and Windows.
So MS chooses which apps come over? What if I want an app that MS hasn't chosen? What happens then? Should I stick with WP if I can't get all the apps?
Why develop for 3% of the market? Will the apps work well on low end WP hardware? Even though you're talking interface looks it's still development time. Will developers bother? MS would have to make if fairly easy to port the app.
What do you do now if the app that you want is not in WP?!
3% of market share is enough for big apps, but as you can see in your phone is not enough for apps that aim to a smaller share of the user base. That's why we need Android apps to fill the holes.
Android apps will improve their performance with ahead of time compilation, supposedly Kit Kat is implementing this but I don't know how many apps are included since launch. The other big impact in performance is caused by apps misbehaving with background tasks. Microsoft should impose more strict rules in the windows store, as Amazon does.
My point in all this is simple. In what way is this better than simply buying an Android phone? Why buy a WP? What am I gaining by buying a WP? What makes it at all attractive?
The whole point of WP is that it's supposed to become cross platform with W8. Where does this fit in?
There are lots of people who simply despise Google and Android and are on WP. Do you see them sticking with WP if this were to happen? I see WP tanking if this were to happen because the users are different compared to say BB.
I have no doubt there will be some who will be completely happy if this were to happen but I won't be one of them. I want apps for WP, not a botch job.
I buy Windows devices because I love the UI, the tiles, Microsoft services, integration with Windows 8 and XBOX, security, productivity. The top apps, where the user spend 70%-80% of their time, should be native with a distinctive user interface, but Microsoft can't achieve the same with small apps. Of course Android and HTML5 apps hurt the user experience compared with native apps. But most people would chose these alternatives rather than NOTHING. So the key is allowing only Android apps that aren't economically viable in the platform.
Android is becoming a standard used in a myriad of compatible platforms (Android forks, Jolla, BlackBerry, etc.). Probably in a couple of years more than 50% of the devices shipped with an Android runtime won't use Google services. Microsoft could adopt this massive platform and its millions of devs to increase the reach of Windows and their services.
Maybe the unification of WP, Windows and XBOX will be enough to reach the critical mass for the platform, but if It's not enough then the alternative strategies should be ready. That's the motivation behind the Normandy device and the adoption of the Android runtime on Windows.
People have to be realistic and understand that this platform won't survive with a 3% of market share, Microsoft is playing their last Windows cards this year, if the platform doesn't take off then 2015 will be robotic green in Microsoft.