Rewards from world quests should not change based on your spec. We don't want you to feel like you need to look at the map to figure out what you want, respec, then look at the map again to see what changed.
So you want us to feel like we need to look at the map to figure that out, respec, log out and log in again, then look at the map again to see what changed? Because thats how it currently works.

If a world quest reward is changing its state while active for your character in any way other than item level going up, it is a bug. Please let us know which quests you're seeing this behavior on.
edit: I found some in Suramar that were misbehaving; this will be fixed in the near future.

World quests not respect loot specialization?