Personally I still want a bigger WinPh as tablet. Everything is there. I don't even care multi-virusing support. WinPh already have tons of good apps on the market. Fantasia Painter is quite awsome for photo enhencement (HDR simulation), and it is so simple, which is what people want.
And WinPh already have Office included, which is great. When it comes to tablet. People just want to surf the web and doing some simple tasks, like calender, to-do list, paint, simple games, social app, and etc. And most importantly, be able to explore app store and install "safe" apps with simple brainless one touch of the button. And removing them is not only easy, also "reliable". Installation + Safe + uninstallation + reliable = WinPh7, not Win7.
It was horrible that I couldn't remove evil Google app on my friend's XP/Vista. And same with the Evil MSN browser which is dead and unable to remove.