Nasus balance

I know that nasus is good right now just because of klepto, but can we take a moment to talk about his w? Like, it, at max rank, is a 95% slow and a 50% attack speed slow (47.5). This means that he has what's almost a root that also halves your attack speed. Not to mention the cd at rank 5 is, with 45% cdr (which you get generally with a sheen item and spirit visage) is 7 seconds. It lasts for 5 seconds, so you have a 2 second time when you're not unable to move and unable fight. Forget scaling, he just gets to duel almost anyone top lane because they lose, for a lot of champs, almost half their dps, and are unable to bully him.