Maybe they are worried about newer players hiding them, then losing track of what they are doing. You know the kind of player that doesn't know what they are doing just yet. I'd suggest bring this back from beta, to hide quests. But make it maybe a option that must be enabled in the settings. That way you can avoid hurting those newer players. It's the only reason I can imagine for them to not have this feature. Of course you'd think if that were the case, why are there so many quests that if you walk away by accident, without picking up the next quest in the line, you are really in trouble. Because you come back a week later and your like omg, where was that next quest. idk