Windows Phone needs a few things outside of the OS;
1. Need a flagship device with a killer ad campaign for that device. Stephen Elop said he wanted to make something that was "drool worthy", I am looking for something at that level or the higher level of "graft worthy" (where you are holding it so much, it grafts to your hand and you are happy!)
2. Need a killer ad campaign from Microsoft like the PC Store in your home campaign, but for the phone. Need to show the features and how easy it is to get what you want and move on. Target moms keeping track of a household, or the worker in all of us that commutes and becomes human on the way home(music/gaming/in touch with friends while on the train or bus). Then the twenty something that is doing the social and gaming thing. The grandparents that easily put their grandkids pics on the web and have them on their phone to show with friends on the phone. The family that stays in touch with Groups. TONS of ideas.
3. Apps are something that will come, more are being added daily. Not complaining about it, just stating a fact. Pssst.. Microsoft Research, if you're listening, I would REALLY like a Worldwide Telescope App with my Mango please? {grin} We need a couple of special high end apps, AR probably, like a Disney Parks AR app is one idea.