These were posted from a week to just a few days ago, but they go over what the WoW Dev Team thought of when they made Cata what it is now.
The first one discusses quests, and how hard it was to redo zones to allow for flying mounts in Azeroth (and to make the Cata lore more true).
They enjoyed making the solo quest lines for 80-85, to make the player feel s/he is special, and is contributing to helping stop the Cataclysm (such as repairing the World Pillar in Deepholm).
However, it also was a learning experience. They want players to be able to do the quests their way, and any pace they want.
They also know how cool (and sometimes annoying) phasing was in Hyjal, Uldum, and Twilight Highlands. They know that some players want to help their alts (or other players) through difficult quests, but can’t due to phasing (because one person has already done all the quests).
But it was also immersive for solo players, which gives a feeling of accomplishment.
They talk about the Molten Front dailies of 4.2, and they say “we want to make more of this”. I very much disagree, as it reminded me so much on doing the Netherwing dailies.
If they’re going to do it, give us alot more quests. More variety and less… randomness, is required, in my opinion. I want to feel like I’m actually doing something, instead of coming back and finding out the same guy I killed yesterday has to be killed again, and again, and again…
They discuss the lame (in my opinion) quest Elemental Bonds. They agree that there wasn’t alot of character development. Plus, it was too easy. They say they had to make it simple, because they didn’t know what gear type of player would do it. And they know they can do better.