So I just checked and they actually made a post detailing the changes. Health gained per infinity stone was nerfed for the chitauri team, but the damage done by iron man’s gauntlets was nerfed as well. Thor was buffed. I would link the post but I’m on mobile.
it's sad because they won't look at the data after this day 1 "hotfix" either. since once the collect stone challenge is done the villians won't ever win