I decided to try protection out on PTR after reading this thread, and although my average item level is pretty high on my tank offspec, I did have a bit of tanking problems till I figured things out. I used Blood and Thunder mechanic and it looks for me atm, pretty much essential. For me rend ticks for about 250ish and TC hits for about 300, using them on cooldown ended up in Rend doing 2x more damage than TC on one single target. About clunkiness I believe what you guys say is not true, after a Charge and up to the time where melee are already hitting your mobs you have plenty GCDs to put a Rend up and TC right after, and you can also Cleave and drop a Shockwave as soon as they start attacking. That for me was solid enough threat.
If one keeps pulling w/o much downtime Thunderstruck becomes very powerfull depending on the DPS mob killing speed, I tanked on the PTR and the speed was pretty much the one we had in TOC/Ulduar times in a dungeon like Gundrak with random LFG DPS.
Like with soloing Victory Rush is very powerful, and if mob killing speed is good enough, it can be used very well as a healing cooldown whenever you notice your hp droping unconfortably low. This along with the other healing/health talents supports the use of maximum stamina gear while leveling-tanking.
The damage we do compared to live is abismal, in full tanking gear, but considering with the crit reduction from talents we can equip more DPS gear than ever in Cataclysm, dungeon tanking will provide more entratainment than it ever did, especially at higher gear levels.
If anyone has anyother questions, post them here and I'll answer as best I can.