Mordekaiser has been flattened up
He is a one trick pony now: wait for CC from team mate --> unleash 3rd Q --> Profit
His playing style didn't get any more dept nor did it improve anywhere. instead he how can't push lanes as much as before. His shield doesn't load up fast enough if not against 3 enemies and so any kind of bait he was able to pull pre-rework is not going to work.
I know he has been just released, and even I played too few games but this is not a matter of performance (which I recognise can be high if team is coordinated), this is a matter of what "plays" he is able to do and outside of BOOM DEAD Qs there is really nothing on the table.
Before he could be a perfect bait, a great pusher and a treathening damage dealer. Now he is just a burst damage tankish brute.