Microsoft has already done that end-to-end experience thing with Surface and that didn't turn out all that well. Windows phone has been critically acclaimed but that hasn't really made much dent on the IPhone/Android duopoly. And the relatively more successful windows phone devices aren't exactly sub-standard, infact they are quite high quality handsets made by the same manufacturer they just acquired. I'm doubtful how much of incremental improvement end-to-end will do this case.
Surface was a failure in marketing, not the devices themselves (okay, Surface RT was pretty bad). The hardware is great, and people love it, and the Surface Pro is really useful for students and even small time developers, and people generally really love it after playing with one.
For Surface, in my opinion, it was an UI which looked nothing like what people expect from "Windows" (not saying it was bad) combined with hardware that was not appealing in terms of specs vs price. So I don't think the hardware is that great. E.g. 64 GB Surface Pro is now selling for around 900 USD; after deducing space taken by OS, the free space is literally an insult considering the price. If you sell it to me as a full computer, the specs just don't stack up. If you sell it to me as a tablet, it is way too pricey when I can get a significant portion of functionality from a more portable Galaxy-class tablet at a much lower price point. Not sure if marketing can fix this.
