I disagree that the bosses are hard. but i ought to point out why i hate Ao3:
1. Crazy prices of the items
2. Not supporting Hybrids
3. STOP BOOTING!
4. Nobody lets you join their game.

Ohh and a little tip: Get 2 tankers/berserkers , 2 mages/paladins , and 1 PURE dex this will help ease out the dungeon, and bosses are easier if you have Teamwork.