+1 to Nacho's idea. Why not random generated levels made by the computer so OOO do not have to do any work with new bosses and we do not have to wait for so long. Why not mini bosses, random generated, random statuses, random type of monster in monster family? There could be one in every stratum in every gate.
Yes i want quest, but if they ever make quests i hope they are not grinding ones like the one you suggested. I dont want someone to ask me to get certain ammount of materials or to kill certain ammount of enemies.
I want something interesting like quest that get me to new areas or let me fight new monsters.