I'd love to see a PvP themed quest at each holiday. i don't mean "win x battleground dressed as a smurf" but like the ones where you have to do something in an enemy city - like when we had to shoot with that little rifle, that was a blast!
Give the epics that are dropping from event bosses a sell price (eigther the "regular" or if you want to prevent farming f.e. 5-10 g per epic). It is annoying always to delete them manual because you can't sell them.
Itemlevel could be better too - maybe the current LFR level minus 4.
I'd like to see all holiday events renewed, making them more dynamic, mainly adding to every one of them some special mini-game that anyone can play at any level, with a good gameplay and some rewards. Something that is fun to do and that you look for every year, and not simply a task to do.
For example, a whole mariokart-like with rams minigame only aviable during brewfest, snowball fight battleground during winterveil...
A thing i miss alot from old EQ1 days are gm played npc's! Interacting with players in some way. I'd love to see a santa-orc flying around orgrimmar, or maybe headless horseman flying around setting people on fire! Yesh
The one change I would really like to see as a Holiday event is an in game Holiday.....The full unity of The Alliance and the full unity of The Horde... like the day a treaty was signed By Humans, Gnomes, Dwarves and Night elves, and one for the Trolls, Undead, Orc and Tauren. I think this would be a good way to bring a little more lore into the game, and give us something of a "unity day" type event... with a quest say to go to each major city and obtain a Signature from each current Ruler or something. In game items obtainable would be a Faction-specific mount and a race specific mini pet like the Argent Tournament had. Where you choose what pet you want, over the course of 4 years to obtain all 4. Or of course, 4 different toons, each choose one, to obtain all 4 the same year.
I think a great idea would be to make some sort of "remembrance day", where you would sit and tell the tale of the "old days", starting perhaps starting with Akama's "I remember the temple as it used to be.." words or something like that. And then jumping into scenario with your character scaled down to lvl 70, gear and all. perhaps even old talents and abilities for this particular occasion, and going through old points of interest, like KZ, SSC, or unique world events such as Invasion of the Litch King armies pre Wotlk Launch. Perhaps even events pre Cataclysm so that we could actually see why the Deathwing came to SW and why did he leave? as well as destruction he caused first hand!
An other thing would be a "group tales" where you would as lvl 60, 70, 80,.. version of yourselves battle through old ZG, BWL, ZA, or KZ or any other raid, world event, or a big moment in game history that is neither raid nor world event such as Battle for Hillsbrad (make it temporary BG that awards lots of Honor points), or fall of Lordaeron from Warcraft III, Sylvanas' rebellion against Arthas and Ner' Zul, Fall of South Shore, etc, and you could be "reliving" the story you are telling to let's say, the children of Stormwind, inspiring them to become more like you? Or it could be something taking place on graveyard outside SW, where you would remember the old raids and honor all the fallen allies, not only NPCs but the people who we used to play the game with and are in game no longer.
Not to mention the warm and fuzzy feeling this would invoke in the veterans, and let the new people see the greatness in the days of old. Assuming it is just as hard and painful as it used to be, no scaling down! May I remind you that no world first came easy during TBC, Kael' Thas in TK fell almost 6 months after TBC was released, two weeks or so after Black Temple patch, and that was world 1st kill. And don't you dare say those people haven't tried hard enough, it was just a challenge in it's purest form. Let them see that, let them fall in love with the game as we have had.
Damn so many ideas, but this is just one. I ought to apply for job at Blizz.. :P
An hourly-or-so event during Noblegarden that references Night of the Lepus, with rabbits the size of wolves invading and needing to be repelled, rewarding a rabbit mount for repeated participation. And they have the same loot table as the eggs.
I would really like it if they spiced up the holidays and added more to do for the players that have been around for a while and have their violet proto. I just remember how amazing the events were when I was a new player and I had all of these cool achievements to do. ALSO: CHRISTMAS DUNGEON. Or a dungeon or every holiday. Those are so fun.
I'd like to see more Pets/mounts that are worth Farming for. maybe something exclusive with achievements that are a little more time consuming or rare drops. and maybe a transmog Set which has 1 piece drop every Holiday event. a new set tho. not a recolored old set.