World of warcraft: rogues . . . WTF????!?

Rogues . . . yea i spell their name correctly, unlike 90% of the world of warcraft community. WHY DO THEY BLOW SO HARD!!!! i have a level 71 undead rogue, AND I CANT GET HIM UP ANY MORE!!!! I attempt to go and do random dungeons, but sadly my shatty leather armour cant withstand one blow from the weakest monster in there. now i know i should keep trying because they seem to do pretty good DPS when they get to 80 and what not. so does anyone have any advise, tips, tricks or anything about rogues coming up in the new expansion?? much appriciated. That is all.