Event where everyone grind like crazy for godlike powers and clear raids on their level almost solo? Of course not, it would lose all charm if this was up every month.
But having way to level your character from start to max in older expansion? Of course it should be a thing, but why limit it to timewalking? Just enable Chromie time as option to level 10 to 80 in one of first TWW patches for all people who did campaign and get 80 on their main in Khaz Algar.
Maybe we should also get special rewards with different expansion themes for people who pick specific Chromie time and won't switch to another before max level, to avoid both people rushing through warlo.. I mean fastest expac or jumping over different expansion for most lucrative quests. For example MoP could have returning Remix cosmetics.