I am trying to ask you, what are you trying to do? I have made many windows phone/windows apps and I have not really needed anything other than what is built in. If anything is missing, I just make it myself.
Can you elaborate on what exactly you are trying to do, so I may be able to help you accomplish your goal?
Such as launching share bar, rate app, tile update~
I think it's good to have such a platform specific plugin like that..