While we are only three weeks into Destiny 2’s Season of the ... I think the way Leviathan would be best received would be if it arrived alongside its raid lairs at the same time.

However, Bungie also vaulted Leviathan, its two raid lairs, Crown of Sorrow and Scourge of the Past from Destiny 2 itself, so those seem like options to be “reprised” from the content vault.