Is it just me or are Marauders really hard to train?

Kay so, after the 4 days worth of 2x EXP Nexon gave us, I was level 82 and fresh out of Slimeys ready to take on newer and better monsters. Right? Wrong. As soon as I went to check out how I'd fair at Duals, they ate me alive. The EXP/hour was barely any better than Slimeys and the only difference was I was draining pots 3 times as fast. I never remembered having 8x training troubles on my Sniper or Sader, so why is a Marauder so frigging painful? I'm 95 now and it's STILL not any easier to take down monsters with more than 30k HP.

Discuss.