Were Epics retuned?

I usually play, but some years ago I TRed into a paladin and then quit. Now that I am back, I brought him to level 20 and had a blast after going through the chore of getting to level 12 when the real power spike came.

But the actual question is, how TF I went from afk-tanking entire armies in heroics (ok, level 16 elite quests) and taking chip damage of 8-15 (I found a very cool ring that gives me 100 temp HP sometimes when hit and it procs like crazy) to getting pounded by 50-120 hits in EE Borderlands/Devil Assault.

How is the change so drastic?