Welcome to elemental damage where, a single affix is enough to negate most if not all of your RR.
I would not be surprised, if all the damage you managed to do came from aether/chaos on Arcane bomb and Eldritch fire.
The solution to this is simble.
Slap a -5 to -10% maximum resistance passive to Brother Segerious, Sister Crimson and human heroes in FG and AoM.
Unfortunately, Zantain has not decided to go that route.
On the bright side. elemental builds can look forward to this feature in the next community league 
.