I don't understand why people are interested in IV's when a min IV pokemon can take down a gym just as easily as a max IV pokemon, and defenders basically see no difference either.
The way battling works, attackers have all the advantages, and a little difference in IV makes no difference at all, at least in my experience.
I can solo every gym I have come across with an 1800 CP Vaporeon, even if they have much higher CP Pokemon defending. That same Vaporeon, or any other Pokemon, can't possibly defend a gym if there is a halfway decent attacker.
The min-maxing of IVs seems pointless to me.
Right now? Yeah, probably, but having thrown away countless 4IV hatches in the main games, it's hard-coded into me to care about IVs, no matter how meaningless it currently is in Go. Not nearly min/maxing to the same degree here (anything over 75-80% is fine right now) but it's a curse I'm going to have to live with.