Is Darius too strong now?

He is certainly a tough cookie, but hardly op. He is definitely conterable if you itemize correctly, and get an early gank .

Once he lost perma-ult availability he lost that status - I can't even remember if that was this year or last, it's been that long.

If you see him wreck it's likely because people have forgotten how to fight him - or never knew how in the first place.