It was your choice to level an Apocalypse paladin who really has to stand still for some time in order to damage enemies. You are asking for nerf, probably not even knowing about Superbeast morph that greatly increases the number of attacks per frame (Faster Cast Rate -> monsters die faster, so you won't have to stand still for too long).
Point 1: All you had to do is wait for your uberskills because some chars are harder to level up than others.
Oh, yes, Countess and her minions have a specific spell that can quickly kill you unless you use your brain and use your character's legs to do a little dodge. Can you imagine how many bosses with similar mechanics are waiting for you ahead?
Points 2: If you were thinking that you can just stand still and watch the whole screen wiped out of monsters by constantly spamming one skill without moving, you were terribly wrong.
The mod requires you to use different tactics for different situations, so, please, adapt or stop asking for mindless nerf.
Point 3: If you had created a topic named 'help with Countess and Mephisto', instead of 'nerf' there wouldn't be such mixed feedback to your side.
P.S. I hope you already have defeated those monsters or did them with a different character and recognised that your suggestion was wrong.