No, and no. First off link your armory and we can comment. Second, most tanks around here with full ICC gear PUT ON dps gear to tank heroics, if you are coming from the opposite direction you shouldn't be too far off the mark.
I bought dual spec for Protection because my guild doesn't have many tanks. Did okay when off-tanking with them in raids, and learned to use Vigilance for fun and profit. In order to practice solo tanking, I decided it would be smart to go into a lower-level Lich King dungeon at Normal difficulty. So I picked Azjol-Nerub--the level is around 72-75, so even in DPS gear I figured the stats I had would still compensate. Plus it was a dungeon I'd been in plenty of times, I knew the fights, etc.
The other PUG members were thrilled to see me--at first. They were still game to give it a shot when I explained I was a first-timer (I have no complaints about the group members at all), and off we went. We never got past the first boss.
I had done some research, had most of the glyphs I needed in place, and put Vigilance on the healer. Made sure I was in Defensive Stance. I'd already arranged my action bars for a good rotation. I used Challenging Shout and Taunt. Tried my best to tab from one mob to the next, but the cooldowns on CS and and Taunt were longer than I'd hoped. Spammed Heroic Strike and Thunder Clap as often as they were up. But I still had a mob peel off from the group and go after the healer. Got him back, killed that first group, everything seemed to be going okay. But soon I lost another mob, the healer died, and we wiped.
No one quit the group, and we all tried again. The same thing happened, I died early and tried to run back in, only to find my party members retreating toward the entrance with the boss in hot pursuit. I tried to grab aggro, died, and quit the group before subjecting them to any more misery.
Problem #1 is surely my gear, and I'm resigned to the fact of having to acquire and carry around two sets of gear. (Acquisition time will therefore double for both sets, blurg.)
If tanking multiple mobs, between Thunderclap, Shockwave, damage shield, and cleave, you should have no issues holding threat. Spam those abilities more often. Tab Targetting will take time for you to master, but it's an effective tool even for Paladins/Unholy DKs who have few issues with AoE.
Problem #2, I think, is that I was not successfully tabbing to each mob in a group in order to get threat on them, and I'm not sure what the solution to that might be. I downloaded TidyPlates/ThreatPlates yesterday, but I haven't tried to tank yet with that up, and I'm worried that in a big crowd I won't be able to see the plates well enough for them to be effective.
-Don't give up and be patient. Keep to it, you will learn the skills required to tank, if you practice, practice, practice.
Anyone have any ideas? I don't want to give up on tanking, though that was certainly my first reaction--my guild still needs a tank, and I hate giving up on things in general. Are there any macros out there that might help with the tabbing-selecting thing?
Thanks very much...