And now we know why Revive was really removed.
http://3.bp.blogspot.com/-fmHFOBojsSA/VVOWJf9IFdI/AAAAAAAAp1I/d4ho88UqMjw/s640/Ekko_Splash_WP.jpg
In case you haven't heard, here's what Ekko's ult does.
"R: Chronobreak
No Cost
90/80/70 sec Cooldown
Makes Ekko invulnerable and untargetable, and teleports him back to wherever he was 4 seconds ago. Ekko heals himself for 100/150/200 + 20/25/30% (+0.06 AP?) of the damage taken over the last 4 seconds, and deals 200/350/500 (+1.3 AP) magic damage to all nearby enemies on arrival."
Go into a teamfight, blow everything you have while doing as much damage as possible, die, use Revive, press R, deal up to 500 + 1.3% of your AP magic damage in an aoe to anyone that was near your corpse and proceed to clean up.