I would like to see quests that you can repeat, get some new rewards for each time you do it. lets say it allows you to do the quest every few hours if you do it X amount of times you get X reward or something like this.
For example you can do Quest A 15 times to achieve Title Quest Master. Or another example might be a housing item and Quest A might lead to Quest B after completed 50 times Quest B gives X reward. After completing Quest B 10 times go back to quest A repeat it 10 times to get to quest C etc, again the quest would only be repeatable X number of times per day. and the reward for the final quest could be a random item, title, or whatever.
Would be really cool for something like this for end game to keep the level 60 players busy :)
If you can think of anything to add or a better way of saying what I had said please post below!