Why Ekko is op

I believe Ekko is op not because of his insane damage, but more because of his ability to do everything. Let's compare him to talon. Talon in my eyes is one of the most balanced champions in league. He has high potential damage, but with a high risk high reward mentality. You can destroy a squishy but are likely to die while doing it. If you compare this to ekko, Ekko has similar burst, similar mana costs but with a complete get out of jail free card. His ult just makes killing him seem impossible. Riot needs to make assassins more like rengar or talon who can reliably one shot a squishy but will suffer getting focused down while doing so. The reliability of some of these assassins is insane