That would not be a problem if Android stopped competing on Windows on price. Right now it is cheaper, and more feasible, to just get a cheap Android for Android apps, than to deal with Android apps on Windows Phone which would inevitably require more powerful hardware to do the same that Android can do on less capable hardware. It sounds great in theory though.
The real advantage would be clean devices with no bloatware, and the ability to run every app off of the SD card, but that's really where the advantages would end. Plus Microsoft would need to gain access to Google Play Services to make it worthwhile, so they would have to pay the Google tax.
Microsoft just needs to give us an Android phone and be done with it already. No need to emulate, because there isn't anything on Windows Mobile worth switching back to. I'd rather have Microsoft as an Android OEM. It sickens me to see Samsung Galaxy 8 sold in the store when Microsoft could be an OEM and sell their own Android devices in their own store.
I just don't get it. There is no shame in being an OEM. Microsoft was never a serious contender in hardware anyway. The only thing they ever had was the Surface and the Xbox. Zune, depending on who you ask. That's it. I think they have a mouse and a keyboard that people swear by but phones, it just isn't going to happen unless Microsoft adopts to the marketplace. Isn't Blackberry now running full Android on their devices? At Microsoft would be able to move hardware in this space if they adopted Android. We know that the UI would be good. And we know that you would get exactly what you need, without any bloat, if they were to do it. I just can't wrap my mind around it. I would definitely purchase a phone from Microsoft if they were to do this.