This quest is marked as being limited to a max level of 15, and becoming unavailable beyond this level. This is no longer the case. Marshal Dugham still offers this quest for my Panda (lvl 22 out of the zone)

I suspect the same may be the case for other lead-ins quests, although I know it is not the case for the one in Arathi Highlands - Heros Call: The Hinterlands [26542] as this was removed entirely

Just confirmed that [26365] hero's Call: Redridge! is also available after the level it's supposed to max at - 18 - so this also needs an update. I'm guessing that all of them have been updated except the ones that have been removed