I made a tank Wednesday and once i got her to 15 i started tanking, and my dps is rediculous. My dps is almost 2x more than all 3 dps combined everyrun (maybe 6 runs). I can basically solo any current content (level 29). I was just wondering how long this will last and how difficult does it get?
You will be about on-par with DPS around Cata dungeons. That is, if your dps isn't lazy or slacking or just plain sucks. Then at 90, after you've gotten geared, you will probably be at or near the top of DPS charts again, thanks to Vengeance.
1 - vengeance. Tanks and dps actually have pretty similar damage at low levels to keep questing fairly consistent. It's not until you get to much higher levels and characters get much deeper into their spell trees that dps characters start to pull ahead. And until that happens, vengeance means you're usually going to come out ahead. Particularly in dungeons where you're typically tanking multiple mobs at one time.
2 - aoe rotations. Most dps classes don't have access to their more powerful aoe spells that early in the game. You won't even see AoE rotations become more efficient for a lot of dps classes until around level 60. Up to that point, their single target is generally better. Tanks however, get access to aoe very early because you need to be able to generate aoe threat. Hence, your aoe damage is going to be higher, and since you're frequently in aoe situations in 5-man content, you're going to be doing more damage.