If they are going into mobile they better have unique take on it and not just be doing it to say they can. If it looks and works like W8, iOS, or Android then they should not spend he resources.
At the very least, their unique take will be their commitment to openness, which iOS abhors and Android also makes difficult. Hopefully this means we can decide what software to install ourselves, and that we won't need to "root" our phones because they gladly give us root access.
Openness doesn't sell phones to non-geeks. If they cannot do something unique then they shouldn't spend the resources. Also, on a phone, how many of those drivers are going to be closed? Right now it is pretty much video, on a phone it will be interesting.