Maybe a post game feature, like battle frontier structures with this level of difficulty (like the current battle towers) would fit better due to the difficulty curve that is actually implemented in the mod.
Gyms should be hard, but for casual players is too much.
I guess the intention here is that you consciously prepare a team for each gym and you spend some time trainning. Maybe a difficulty config for the gyms would fit better and each player can decide the experience with the mod.