Hear me out, though: I'm not saying we should kill repeatable questing here. Repeatable questing, first given to us in World of Warcraft with the inclusion of the Skyguard and Ogri'la questing hubs, was later expanded upon with the Isle of Quel'Danas as part of the Sunwell patch and has been with us ever since. Throughout Wrath of the Lich King and into Cataclysm, we've seen new daily quest hubs come and go. (Cataclysm currently has both Tol Barad and the Molten Front as hubs, plus other dailies for reputation factions such as the Therazane ones.) I'm not specifically arguing against the concept of having questing hubs that offer repeatable quests for a reoccurring reward.
I'm asking why must they be daily?
Clean your room and take out all those fire elementals
The problem with daily questing is that it can quickly feel monotonously repetitive even if the specific quests you can do changes from day to day or there are specific variations introduced. Yes, the Molten Front changes as you progress through it, and yes, it offers you a choice between the Druids of the Talon and the Shadow Wardens, meaning you can alter which daily quests you do each day. But the quests still end up feeling somewhat like chores that you log on to do every day because you have to or you'll miss out on rep gains or rewards. They serve the purpose of giving you stuff to do, but they feel obligatory. Even the innovations in how the Molten Front progressed (based in part on how the IoQD dailies unlocked as the island progressed) doesn't prevent it from feeling this way; it simply changes which chores you're doing that day.
Blizzard has already done an interesting variation on repeatable questing with the new Darkmoon Faire. This content is behind a gate making it only available one week out of every month, meaning that it can't ever feel as if you're obligated to do it every day. While it still means you're obligated to hit Darkmoon Island when it's accessible, it becomes something to look forward to when it can be done rather than something to trudge through.
Under the light of the full moon, I perform a quest
We can consider all sorts of variations on the daily model. For some quests such as the fishing and cooking dailies or the jewelcrafting ones, I could easily imagine going to the same system used in dungeons today. In Wrath of the Lich King and early Cataclysm, we had the concept of the daily heroic for frost tokens or valor points. This was changed to a weekly system, where you could run seven dungeons for valor points in a given week, giving you freedom as to when and how you did so. You can run seven dungeons in a day, or one a day for a week, or whatever variation you like -- so two every other day, three one day and four the next.
This could easily be adapted to questing, so that instead of logging in for an hour to do your dailies and then logging off, you could do them all on Saturday when you have the time to devote to it. Or you could get them out of the way on Tuesday night, or choose to do two or three on Sunday to catch up for the week.
Another variation possible would be similar to how archaeology currently works, with unlimited repeatable quests that have a chance to provide a reward. You could do the quest over and over again, and instead of gold and experience or reputation, it would give a chest with a chance to contain an item. You could tweak this reward to be whatever you desired, a token that grants reputation, a transmogrification weapon, piece of armor, or what have you. The frequency of how often this could be repeated could be tweaked, as well; it doesn't have to be truly unlimited.
Imagine being able to run this quest five times a day but only once every hour. You could design quests that are infinitely repeatable but with long cooldowns (say, two to three hours) to keep players from feeling forced to sit in one spot and grind the quest out over and over again for that item they want. You could even allow the chest or satchel with the reward to be bind on equip so that players could run the quest on all their alts and then mail the satchels to their mains, if desired.
The purpose of contemplating these ideas is to try and break up the pattern. I think daily questing can serve a purpose and should probably be maintained in future design, but I also think it can be supplemented with variations like weekly, monthly, time-locked and other options for repeatable questing content. That would give players a choice in which they feel like doing with the time they have available. As time progresses, World of Warcraft can only benefit from having these options.
World of Warcraft: Cataclysm has destroyed Azeroth as we know it; nothing is the same! In WoW Insider's Guide to Cataclysm, you can find out everything you need to know about WoW's third expansion, from leveling up a new goblin or worgen to breaking news and strategies on endgame play.