Normally other than bloat removal, root not necessary for me. In the Zmax Pro's case I would use it to right the infinite wrongs ZTE slopped into every corner of this phone. They ship every other food stamp device of theirs with 5.1.X and should have included it with this one too, it would have been perfect. They singlehandedly destroyed the Marshmallow experience for me lol....
With that said, I don't have too many hopes for the poor souls working on 7.0 for this phone. I'm sure their building has baton-carrying guards and suicide nets