@Kaylessa, Do you consider killing the same boss good gameplay? What about new Holiday Worldquest, Holiday PvP brawls, Holiday World events…then add the cosmetics like Arfus, mount…etc that are related to a limited time event to a vendor for candy that you can farm from the boss or that other content. Yes, you’re right Boss participation could go down but you can fix that too, Instead of adding just 2 rings, 1 sword and 1 plate helmet…Add a whole full catch up holiday gear set for every class or make it drop the last catch up gear + evergreeen rewards like XP potions, Stat runes…etc, maybe add 1-2% bag that could contain mounts from previous raid, dungeons, reputations …etc like the did before with healer / tank for LFG (https://www.wowhead.com/item=69903/satchel-of-exotic-mysteries#contains
).
That’s a good first idea, similar to the mount for Alliance/Horde from Timerift that you can gift to other players or the Salamander from Forbiden Reach that you can trade.