Is it me, or does Morde seem to lack damage when compared to mobile assasins such as Khazix?

I thought juggernauts were suppose to wreck your face, if they ever got close enough. That seems true for assassins such as Rengar, or Khazix, but this is not true for Mordekaiser. His Q takes forever to get to the third swing and he doesn't have easy access to attack speed without giving up ap or tankiness. He tends to get rekt by assasins 1v1.

I feel like compared to melee assassins, Mordekaiser doesn't do damage. The Q takes to long and really doesn't do that much damage even when build as full AP/AD.