Don't recall if there's anything canonical that supports it,
but I've seen it argued that Palpatine never wanted a stable empire to begin with. Rather, he wanted a galaxy of suffering and misery to fuel his own dark powers, facilitated by a mix of civil policies designed to make it as dysfunctional as possible while it lasted
and pure, relentless cruelty. (With galactic domination
not being the final step most are led to believe, despite mainline media putting it front and center.)
Naturally, the resulting incentive structure would've encouraged the worst of the worst to rise through the ranks and enjoy free reign to torment and torture their way across Imperial space. And who better to do precisely that than Ol' Wilhuff himself?