Came across this thread on twitter (https://twitter.com/ObviouslyZelryn/status/1788718837094859210) and did my own testing.
When selecting Legion or Warlords timewalking for the first time, neither quest that leads to the intro scenarios for those expansions was given automatically by Chromie like they were in the past. I did this on a brand new level 10 allied race character.
A level 10 Alliance character can go to Stormshield and waterwalk/use a fishing raft to get to the beach by Lunarfall, where they can start the quest. A level 10 Horde character would have to either waterwalk/fishing raft to Gorgrond and get picked up, get summoned to Bloodmaul Slagmines by 2 players, or take the water route all the way around Draenor to get to the starting quest.
I did this last on a level 12 yesterday.