While I struggled through my first heroic region, I realized the easiest way to win was to simply counter the gimmick presented on the map. I use to think it was to power through with higher level teams, but then I was left with weaker factions that couldn’t do the same thing. What ended up working for me was figuring out the strategy, then applying the exact army to each leader per faction.
For example for the first heroic, to prevent the enemy kobold miners from leveling up while mining, I kept setting unbound dragon eggs on the mine. I was lucky I got exploding hatch talent. I initially tried banshee possession, but it simply lowered the kobold level back to base, a real bummer!
I was finally able to clear all of Heroic Elwynn Forest that way.
If the rest of the community has tips, please share. I struggled on the normal Un’goro crater T-Rex stage, beat it by fluke, can’t wait to see how much harder it is on heroic.