Just a minor change to Zac's lore, which would make ALL the difference
Make his Parents be alive and well and let him visit them every now and then for some tea, cake and getting some advice from Ma and Pa.
Hell, he is Zaun's Superman, even Clark had Martha and Jonathan Kent!
Just by changing this crucial detail we'd have a new and improved Zac without having him lose this light-heartedness that made him stand out from all the gloomy guys and gals from Zaun.
http://img06.deviantart.net/e752/i/2013/133/0/9/happy_mama_day__by_myth1c-d657zgs.jpg
(Also, it's saddening that I had to go through so much "fan art" until I finally found a fitting piece of art for this thread...)
for a second
Meanwhile in Zaun...