Mordekaiser is a tanky AP with great sustain and nuke.
CC shuts down Morde, but what does CC not shut down?
If a champ's "counter" is hard cc, then it is likely that the
champ is very powerful.
With reference to the current meta:
Mid lane: Probably the best lane for Morde because his
kit forces you to push. You can of course last hit only or aim your
abilities so you don't push, but then that wouldn't be using your
abilities to their fullest.
Top lane: Sub-optimal for Morde because Morde will
always push. The lane itself is too open to ganks and that doesn't
bode well with your kit that is designed to push.
Bot lane: Very nice for Morde due to there being a
support. The wards and the protection that your support provides
should allow Morde to push…