At the current gamestate we NEED a way to expand the empire without taking every goddamn single provinces by ourselves, coring, and adding them.
There is no way around that, the Emperor has already enough work to do to even keep the empire together, he cant be bothered sucking up huge amounts of AE and loosing monstrous amounts of admin just to hold it together AGAIN. Currently the smartest thing to do as Emperor is to just drop responseabilities and go full-ego mode, expanding inside HRE, and only allying electors to stay emperor, destroying the HRE
This. It can't all be on the emperor because the AI will never be able to do everything. Without massive player intervention, the Italian states leave every time.