Since the release of the Warband feature, world quests now offer a bonus the first time you complete them. I think it would be nice if there was some way to easily see which world quests have already been completed by a character.

I was thinking either use an underline to show that world quest has not been completed yet:

or desaturated text for world quests that have been completed:

I like your idea 🙂
I will see if there is a way to query if there is a bonus for a WQ

I have unlocked world quests now - but I cannot find any with this message on them.
Also, from what I can see, it looks like you might be able to query if quest has this bonus enabled (Haven't been able to find it yet, but it should be there).
However, I fear that once that has been completed on a WQ, it just appears to the system as if it didn't have a bonus at all. (Like there is no difference between quests without a bonus and quests that had a bonus but has been completed)

The world map must be getting that info from somewhere.

World Map:

Angrier World Quests:

Try adding this in Modules/QuestFrame/QuestFrameModule.lua, on line 414:

button.questRewardTooltipStyle = TOOLTIP_QUEST_REWARDS_STYLE_WORLD_QUEST