I'm mostly referring to PVE tanking. Here's the breakdown.
Trolls have Berserking. Even at 100% it is a decent gain for initial rage and a minor amount of threat (from white hits). Even as a DPS the 10% is a huge buff, if there is AOE damage you can fully utilize the 30%. The tiny bit of health recovery saved me in Vanilla a few key times. It's pretty abysmal tbf, but when you see your HP climb up by a tiny bit and then swung at for what would have killed you, then the healer gets their heal off? It's fairly seldom you'd ever see it happen, but man does it feel good when it does lol. Granted, these racials don't get a lot of love in PVP.
Undead gets an extra fear break, which isn't exactly a make or break since Berserker Rage does this as well. Better in PVP if you're getting chain feared, but you're likely to see a heartbeat resist, diminishing returns, or break on damage anyway.
Orcs get a huge stun resist which makes them amazing in PVP, and decent in PVE. Blood Fury is only good as a DPS. The +axes is rarely used as most tanking weapons are swords/maces. Again, better for DPS or in PVP.
Tauren get a bonus to health, which only matters if a swing would have actually killed you and the extra health was above what would have killed another warrior in the exact same situation. War Stomp is great for dungeons (other than when you cast something you cannot dodge/block/parry) and decent in PVP.