Champions are a DPS class. They do top tier single target damage and are far and away the best AoE damage class in the game. Power use is not generally a concern. Heavy armor allows them to survive damage that would destroy other dps classes and gives them the ability to instantly convert from DPS to tank for even more survivability. These advantages are balanced out by removing all avoidance abilities while in DPS mode.
The post Moria world leaves us with two issues. First, the reduction in overall B/P/E has greatly reduced the penalizing effect of removing the Champions avoidance. This leads to an imbalance between DPS output and survivability especially in group encounters. If average Fellowship healing can keep a DPS mode Champion alive while the Champion is tanking an entire group encounter the purpose of the tank classes is jeopardized.