I've seen videos of people doing MP10 bosses that last 20min + and they don't enrage. Did Zoltan and Siege on MP3 with full group yesterday and boy was it fun learn that they had enrage timer. Why not let people have fun working on uberbosses without a time limit? Did we not all agree that this was a bad mechanic and blizz removed it from the game? Apparently not....
Because its not supposed to be easy. Its something you work towards... It should be every players dream to be able to do ubbers on MP10. Then its no good if they didnt have an enrage timer, so every single moron could just get enough EHP and win. Now you got something to strive for, if you wipe to enrage, it means your playing a MP lvl thats above your characters gear level. Now the game finaly have some end game which isnt a cake walk, why should you ruin that, you got 10 deficulties to choose. Pick what suits you.
Currently played toon: https://eu.battle.net/d3/en/profile/Rage-2973/hero/97362116