Aye, there's even video evidence of this on WhyCalibur's playthrough of Maelstrom Prison ( http://www.youtube.com/watch?v=3uLlsMSxZjM
). They begin the encounter at 10:30 and by 13:00 minutes he's already enraged.
Last year when I stopped playing (Have started again) Maelstrom was a sneeze even on hard mode as long as you met the basic requirements for stats and used your brain.
Now I don't even see how it's possible to beat him, since He's already enraged in less than 3 minutes, unless you're supposed to now ignore the adds or some such BS.