As this is my prot build thread, I decided to post this comment here rather than make a new thread. This is purely discussion only as I am not going to try this build.
Anyway, after that disclaimer, there's a new build making the rounds. In it, many prot talents are given up in the favor of arms talents. Before any more dicussion I will link an example of this kind of build. Understandably it's in the works, has limited viability, and can be tweaked in any number of ways. This is just one example, so no arguing over the finer points.
http://www.wowhead.com/?talent=LA0I0fht00rR0bZZMItrx0zid
What's the purpose in this build? Main tanking. It has absolutely no viability as a trash tank. It should only be used if there's another prot warrior in the raid stacking devastates. It should ONLY be used in a 25 man raid where your offtanks can keep up sunder and can adequately tank the trash.
Why this build? Well let's go back to what I said about how a tank needs to increase their dps. This build does not give up much in the way of survivability. What it does give up is a lot of the prot threat tools while picking up Arms single target massive threat / damage increases.
There are prot warriors, main tanking, pushing 4.5k dps with this build on Patchwerk. The reason why is you can chain Revenges and Shield Slams almost nonstop for incredible damage and TPS. You won't see anyone, ever, pull threat off you with this build.
You will also be a garbage offtank and you will be worthless on fights like Sarth + 3 Drakes / Gothik. You need to respec for Sarth + 3 Drakes and you need offtanks to pick up the adds in Gothik. But on fights where you are single target tanking bosses, you will be the IDEAL main tank. Most damage, most threat, and perfectly fine on survivability.
When dual specs come out you may see more and more warriors taking this as their boss tanking build with a more traditional 15 / 5 / 51 build for trash tanking.
Any ideas or comments? I personally will not be taking this build. I do not always MT bosses in my guild and frequently dps because I am one of the best dpsers in my guild even when I'm prot. When dual specs come out my second will be fury.