This thread from Wowhead had a great response regarding improvements to Protection Warriors come WotLK:
I'll name a some significant buffs to Protection that I can think of off the top of my head:
1. Strength now grants 1 block value per 2 points. Stronger blocks, stronger Shield Slams.
2. New multi-target spammable attack and dot, Blood Bath.
3. Improved Revenge now increases Revenge damage by 25%.
4. Incite is taking Defiance's place in the talent tree, greatly increasing the critical chance of often-used tanking abilities.
5. Last Stand's cooldown is being reduced to 6 minutes.
6. Improved Disarm now, in addition to reducing the cooldown, increases all damage taken by the target by 10%.
7. Concussion Blow now deals damage based on Attack Power and causes high threat, and its cooldown is now 30 seconds.
8. Improved Shield Bash now increases the damage of Shield Slam in addition to its current effect.
9. Vigilance is a new, amazing utility ability to help control problem aggro-pullers, especially in smaller instances.
10. Stalwart Protector grants free rage for parrying and dodging.
11. Unique to Protection warriors is the new mechanic for Critical Block.
12. Sword and Board grants more Shield Slams and even better damage output and rage efficiency than you could get from previous talents.
13. And as icing to the Protection talent cake, Shockwave tops the tree off with a cone-aoe heavy threat stun that lasts 4 seconds on a 20 second cooldown.
14. Heroic Strike's bonus damage was increased by 50% across all ranks.
15. Mocking Blow can now be used in Defensive Stance, and has a 1 minute cooldown now.
16. Thunder Clap now scales much more powerfully with Attack Power.
17. Shield Bash now deals damage directly based on Attack Power.
18. Sunder Armor's threat scale with Attack Power.
19. Spell Reflection's base rage cost was reduced to 15.
Prot Warrior Improvements for WotLK
Moderator: Demon Hunters
Prot Warrior Improvements for WotLK

At the brink of danger I stand. Clad in armour, shield and sword in hand.
I sure will. Right now there is the suggestion (which was my first thought when I read about the ability) of changing it to a radius effect. A cone effect might be problematic as far as gathering up mobs and retaining them goes. Overall, I'm just exciting about the major improvements to Prot War tanking for multiple mobs.
-Heart
-Heart

At the brink of danger I stand. Clad in armour, shield and sword in hand.