An El Nino peaking at 1.0-1.5°C for the Nino3.4 region would be moderate. The 2015-16 El Nino peaked at 2.6°C and had four months of 2.4°C or higher. The 1997-98 El Nino peaked at 2.4°C (for two months), and the 1982-83 El Nino peaked at 2.2°C.
I wonder if El Ninos are getting stronger. A 2016 article from Columbia University's Earth Institute says "It's a tough question to answer."
It's certainly true that ENSO seasons (July-June) with an El Nino are getting warmer, by about (eyeballing since 1970) 0.2°C/decade. The same as the globe overall: