It's not really the pre-TBC loot, you don't get that many feral gears before TBC came out, and the few that existed were obtainable only by raiding AQ40/Naxx, and they were hybrid! TBC suddenly has more feral gear in one map than the whole pre-TBC WoW, all the cats and bears suddenly improved alot.

But put in perspective, all other classes have been getting DPS upgrades as well. It's just that their gears were already quite good from raiding so the improvement wasn't as dramatic as feral druids. Whatever mangle/FB numbers you can do, the geared rogue can easily beat you.