^Too small; DR
Yeah, the Cata expansion ruined the old zones in one detail: Too linear. They are basically now one long quest chain. If you want to enter a zone just to pick up that single quest line with the nice gear reward your SOL.
That's really not true, not any less than it ever has been. There have always been chain quests. You don't have to go sequentially through each zone (other than some of the starter 1-20 zones). Each zone is divided into hubs, but you don't have to complete one hub to move to the next one and pick up a different set of quests any more often now than ever.
I've got 10,000 completed quests in my main's statistics, I'm a Loremaster and I've got four 85s, so I know my questing.
They are more linear, and they don't have you bouncing back and fourth between EK and Kalimdor like they used to. To be honest, I'm glad. There were times it would take me an hour or two of play time to do nothing but travel to hand in a few quests. It helped to make the world feel big, but it was a bit of a drag at the same time. The quests in the new zones actually flow perfectly if you're a first character without BoA heirloom items and the guild experience boost, but I admit that if you do it's easy to fly right through a zone before you've seen half of it.
In the end, there was nothing in the old days that rivalled the brilliance that is now Silverpine, Stonetalon, or Eastern Kingdoms as far as questing goes. So many of the zones are just so fun now.