Bad for users. We'll get half-assed ports everywhere. We're already lucky some reluctant devs are taking the time to at least make a native port, but with Android apps running on WP? Even those on the fence will go down the (Android) drain.
Take a look at BB10.
OK - I don't necessarily Microsoft should or will do this, but I'm going to continue playing devil's advocate because I don't find the reasons against presented here convincing. I don't see why it matters to the user if the app runs in the WP runtime or the Android runtime. Users care whether the app is good quality, useful, stable, entertaining, well designed, etc, not what language it's written in or what APIs it uses.
Bad for developers. Rather, the ones that don't want to exert any effort. Knowing how inefficiently Android runs, and how low-specced WPs are compared to Androids, devs would be flooded with requests to make the apps smoother, be more efficient, and other sorts of requests along this line.
WP users are already quite spoiled with the smoothness (and the design) standards set by Microsoft.
Several points there:
- Well, bad developers will write bad apps anyway, and users will be dissatisfied with them. In reality, the market will decide what level of quality is acceptable and anyway, Microsoft will still control which apps go into the app store (assuming they don't adopt Google Play). If Android developers are flooded with requests to make apps smoother, perhaps they will do so?!
- I don't agree that Android runs inefficiently (in comparison to Windows Phone). I would agree that WP sometimes responds more quickly on cheap hardware (i.e. something happens when I touch the screen), although it varies from device to device. I don't think it's faster than Android (i.e. the action completes, e.g. an app starts up and is usable). Anyway, if there is a difference, is it down to the runtime, or the underlying OS, or the claimed 'better optimisation'? It may be that Android apps run faster on WP - could be a selling point!
- Are Windows Phones underspecced compared to Android phones? As far as I can tell, for the same price, you get similar hardware. It might be true that the average selling price of a Windows Phone is lower than an Android phone, meaning that the average performance will be less. However, users' expectations will also presumably be lower with cheap hardware, and anyway the device will run more slowly whichever kind of app it is running.
- The point about design standards is a fair one. Again, Microsoft will presumably control which apps can be run, so they could impose certain design standards on 'Android' apps. This means more work for the developer, but still much less than rewriting the app for WP (which would anyway require the design to be changed, and much more).