I think, what Microsoft need is a good tag line that's tangible and empowering, something that make people want to be part of. Not "more colorful", not "honestly", these are so vague and detached from anything that would push people into action. Don't always make it sounds like you are begging people to use your stuff.
Windows Phone is "not for everyone, but made for you", is in the right direction but still not enough. Why not just "Windows Phone, embracing your individuality" or something like that?
And Surface? "It's not a laptop, it's not a tablet, it's Surface". What does that even mean? Consumers still don't know why they would want to buy it, they don't know any attributes of it!!! Why not "Lighter than a laptop, More Powerful than tablets, it's the Surface"? Or even just "Lighter, More Powerful"? People would suddenly know what this thing's key features are and you already provided two good reasons to buy it.
Office? Last time I saw an ad for Office that said "Now you can take your homework on your vacation". It made me cringe, I mean, yes, working on vacation is definitely what we all want to do. And what does that tell us about Office anyway? Why not "Office, always exceeding expectations", or "Office: Faster, Easier, but more Powerful than Ever", or even just "Office, More efficient at work, More time for Vacation".
People would almost always ask you "why" you are buying a MS product, but rarely for Apple, or even Google stuff now. Why? Because they already have ideas planted in their mind for those other brands, but Microsoft is just a vague term that constantly reminds people of "BSD" or random bugs in the older Windows.