You say we should avoid repeating apt and rpm. That's all very well, but what about us windows users? I doubt Microsoft is willign to leverage windows update, windows' closest analogue to this, and I'm really not sure how, say, Mac OS, or some of the less mainstream OSes would cope with this.
Or what if you're not root on a unix box? you can't rely on apt or RPM then.
So we're going to have to write a package manager for these situations anyway. While I agree that interaction with apt an rpm is a good idea, it should not mean we shouldn't write our own.