According to Bestiary, Gordunni Shamans should have Fire Nova Totem, which they don't seem to be using
Grimtotem Naturalists, while out of bear form, should be able to use Rejuvenation and Wrath. In bear form they should use Maul and Demoralizing Roar. It would seem logical for me that at least the ones who start as casters can also shapeshift, although I can't confirm it.
According to Bestiary, Grimtotem Shamans should have Fire Nova Totem.
Zukk'ash Tunneler seems to be missing Pierce Armor, Wasp seems to be missing Poison.
Arash-Ethis didn't seem to have Chain Lightning or Shock.
Northspring Roguefeathers can use Exploit Weakness from the front, Windcallers don't seem to be using Enveloping Winds
Edana Hatetalon should be elite prior to 2.3. In addition, she didn't use any abilities despite being a caster mob. Valkyrie Database says Chain Lightning, Lightning Bolt and Lightning Cloud, same as in retail, and this Wowhead post seems to confirm at least the cloud for retail TBC.
Hatecrest Screamers don't have Sonic Boom and Renew. Hatecrest warriors seem to lack Disarm (and maybe Defensive Stance), Myrmidons seem to lack Net, Sorceresses Blizzard and Frostbolt, Serpent guards Frost Shock, Sirens Lightning Bolt and Wave Riders and Wave Riders Geysir.
Lord Shalzaru doesn't seem to be using Frost Shock.
The levels for Feathermoon Sentinels are all over the place, ranging from 56 to 65 with many of them being somewhere in between. I wouldn't consider it a very trustworthy source but TBC era Wowwiki says 65 which does seem right at least. I could imagine them having been 55 in vanilla and the weird level range being there because their level information is based on both vanilla and TBC.
Quest Gordunni Cobalt can't be completed, "Gordunni Dirt Mound" doesn't appear as you use the shovel upon the blue glowing areas on the ground
In Testing the Vessel, you can get Muisek from the same wildkin many times, same deal with the follow-ups.
Same issue with Screecher Spirits, you can get the credit several times from the same mob.
In Yeti skin quests (both factions have their own versions), you should be able to get the relevant quest items from skinning the mobs besides standard drops. In addition, Perfect Yeti Hide has very high drop rate and similar to so many other items of the same type, (like #1652), it keeps dropping while you already have it in your inventory, a major annoyance as you can't skin the mobs without removing the item currently in your inventory.
In "Zapped Giants", the giants couldn't be shrinked and Minituarization Residue doesn't seem to drop from their elite forms, making the quest uncompletable.
Prior to 2.3, "Dark Heart" was an elite quest (due to Edana Hatetalon being elite).
It's obvious from the quest objective that Weapons of Spirit shouldn't complete instantly. A quick search didn't yield any information to how worked in TBC, but the Cataclysm version probably works the same as the quest chain seems virtually unchanged in general.
Rescue OOX-22/FE! has the same issues as Tanaris one (chicken "dies" after first fight, starts moving above running speed after first scripted encounter, doesn't stop to fight if you get in combat)
The Videre Elixir is completable (besides jumping from the back), but the wall simply becomes passable and the gnoll keeps standing around instead of going after the bait. As you can see from the picture in Wowhead, the wall should disappear and the gnoll should move. In addition, the building seems accessible for a long time after using the item, this comment gives some clue about the timing involved.
Breadcrumb quest Camp Mojache should be available in all capital cities, it's currently only available in Orgrimmar.
Freed from the Hive doesn't have any RP. Wowwiki has the details. In addition, looks like you should have to attack the pod in order to free him, right now he just spawns and quest completes shortly after.
Jonespyre's Request shouldn't be available until you've completed Morrowgrain Research for Arch-Druid Staghelm. It's worth noting there's two versions of the quest, one available at Stormwind and one at Feathermoon Stronghold.
In Wandering Shay, Shay doesn't follow you, rendering the quest impossible. In addition, there should be some RP text, TrinityCore/TrinityCore#5156 lists some sourced to retail video.
Freedom for All Creatures is completely unscripted. This video shows a pacifist run, although the quality is crap and I can't make out the details. TrinityCore/TrinityCore#4823 has a readable transcript of the dialogue. Since at least one of the lines is correct as it's the same as in Wowwiki, I'd suspect they aren't pulled out of thin air, whatever the source might be.
Mobs
Quests
World
Not tested