Repeatable quests exist already, they're called Leves. They exist as Battlecraft, Tradecraft, Fieldcraft and Grand Company depending what you feel like that day. Different zones offer different flavours. I suspect SE wanted to do something slightly different than the standard WoW style. While you can only get so many per day (forget the number), I believe the idea is to mix them in with FATES, dungeons and (if you want) some good 'ol grinding. The EXP boost from having a higher class leveled also helps. A number of sideline quests only appear once you get to a certain level, or spot in the main storyline. You may find some you missed on your second time through some zones.
If you are constantly maxing out Leves every day, while also the doing the others, perhaps you should consider putting the controller down and going outside for a bit and exercising something more than your fingers ... All things in moderation![]()