No nerfs - on any toons, ever. A nerf to a particular character does nothing but cause a trickle down series of nerfs. Nerf one guy, then all of a sudden there's a replacement character that's OP. then that toon is nerfed, then the next one... then one day we're all hitting each other with flowers and singing ring around the rosy wondering what happened.
Just build a counter team or a team that can take the punishment. I had a hard time with Wiggs and Lando for a long time, but it's OK now - sometimes I win, sometimes I lose, doesn't matter too much to me anymore.