out of the 7 fighting classes I currently have 3 at rk 50 and the rest is bellow 22. I want to focus on crafting/harvesting so my other figthing classes will remain at this lvl for a while.
Nevertheless I still like doing quests, for the stories they tell but also for the fun of it.
I can easily do most quests with a rk 50 class, but when it comes to end the quest I am stuck with 3 choises:

1-end the quest with my rk 50 and loose the xp
2-keep the quest unfinished but with only 16 active quests, I will soon be unable to do more
3-abandon the quest.

why not change the system a little bit and give xp scrolls as reward instead of raw xp? this way, we could do all the quests we want and we could still be able to use the xp scrolls for another job when it reaches the proper lvl. Just make sure that rk 10-20 quest give a scroll that can only be used on a rk 10-20 class and that's it.

so you would have

quest 1-10 => reward: scroll lvl 1 usable by rk 1-10 classes
quest 11-20 => reward: scroll lvl 2 usable by rk 11-20 classes
and so on.