Yup. There are people that had high quality epic items prior to burning crusade, and after fifteen minutes in outland had replaced half of it with blue, or maybe green, world drops. So, yeah, in 9 levels expect to have entirely new gear, and if you don't by 60+, then you're doing something wrong.
Edit: Good choice with the warlock, by the way. I'm not sure what kind of guild your in, or how serious they are, but you're one of the required classes for Gruul's Lair, High King Maulgar. Once yall get that on farm status it's just free epics - plus it's fun to run large raids.