I know that repeating a quest has to have a penalty, otherwise people would farm maybe 8 different quests in order to get to level 20. However I think its a little ridiculous that TRs have to preplan out their leveling strategy and make sure they maximize n/n/n/h/e combos.
What would be the harm in having repetitions decay, like 2 or so per week? You still will never get the first time bonus back. I think this would be beneficial to level 17-19 TRs who can then casually get XP doing raids and relevant content if they want to slow it down a bit.
Maybe its a small issue but it would be a welcome change in my book. I think it would be relieve a little stress about making sure you leave enough of the finite xp in later levels.
Plus it sort of gives a little buff to the casual player who isn't trying to get 10 TRs done in 20 weeks.