if zag’s only role is to burst down props, you can just use nova liberators for that. and nova can go around clearing the map, too. if zag’s banes are used on the infested, then there will be fewer for the props. being extremely dependent on ally for defense is also a huge drawback. zagara doesn’t scale well into later nights because her economy is already at max saturation early on and the only thing that gets better later on is having all the upgrades finished, whereas the number of enemies increases dramatically.
avenger means you need more banelings to kill stuff because enemies get more hp.
if your job is just clearing, han and horner do a better job at that.
if your ally is swann, it doesn’t matter what commander you use.