I'm sorry. If you think the bosses are OP you haven't been fighting the mobs. You have to do very small pulls in elite, or move glacially slow, to kill those anoying mage's and their purple goo.

Just saying, I view most bosses as nap time after I used a few hundred pots.

The only boss I can possibly see people argue as OP is inan'hesh which requires a high dps team. However, I think he is still doable.

Remember if you didn't fail on your first attempt here and there the game would become boring.