No I actually think it's a bit bad. I average 14 to 16hrs too, but that's with 5 to 6hrs of screen time, and half of the time on LTE which would eat more battery that WiFi.
High android system usage of battery suggests a background app using system resources, like Tasker, Automate It, Llama, Twilight, IFTTT, Lightflow, etc. How is your phone configured and can you list the apps installed?