Blizzard, no please don't do that.
Scenarios are boring as hell. Other than as a single-player device during questlines, they are repetitive, uninspired and their lore-telling value goes down the drain by the desire of groups wanting to clear them as fast as possible. Its hard to be immersed in the story, when an arcane mage tells you to "hurry the f*** up, I want to farm here, not wait on some casual staring at text".
Besides, due to the asinine notion of making scenarios non-role specific, they are also hilariously easy. Its not immersive to kill someone possessed by an old god withing 8 GCDs, just because the Scenario mechanics dictate, that the fight must be solveable by a group of 3 mediocre dps.
Regarding Lorewalkers: I can hardly think of anything that would be so massively out of place in a place like draenor, than a faction of quill wielding historians. What people in their love for the faction (which is understandable, given the massive delusion of accomplishment that faction gave players) tend to forget: In Pandaria, a Land wrapped up all cuddly in peace and harmony and balance and cr**, they fit in (badly, but thats just my opinion). In Draenor, they would not.
I would rather see development resources spent making new 5man dungeons and epic attunement questlines, than wasted on Scenarios.