Ekko's damage is pretty intense
http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2186023640/46796382?tab=stats
Ekko just barely didn't do more damage than Annie and did 2nd most damage overall. His build says he went almost completely tank while his stats say he was their AP mid.
I'm not even sure how he did so much damage.
&
are extremely strong right now (even past nerfs) and Ekko has a kit that allows him to abuse them extremely easily. This combined with his innate damage on his kit added to the CC and utility means Tank Ekko is still quite strong even with the hefty nerfs.