The one thing that I've spent more time on than anything else since Cataclysm release is not exploring, instancing or working on my professions, it's doing the new cooking and fishing dailies in Orgrimmar. I currently do them on five characters per day, usually before getting started on anything else.
I'm really grateful for the new fishing daily in particular. I've talked about my personal history with fishing before and how it didn't really manage to hold my interest until I started doing the Shattrath fishing daily. The problem with that was that I still had to level to seventy without having much motivation to fish, and starting the profession from scratch every time one of my alts reached the Burning Crusade level cap was impractical and tedious.
With the new daily being available as early as level ten, it's easy to get into the profession right from the start and work on it on the side as you level up. You'll still gain levels much faster than you'll gain fishing skills, but with any luck you won't be as utterly unprepared for any later fishing endeavours as you used to be. Let's not forget that just completing the daily will grant you skill-ups as well, regardless of how much fishing you had to do for the quest (if any). This is particularly valuable in the later stretches of the profession when skilling up by even one point takes quite a lot of casts.
If you're rolling an alt on a new server, doing the fishing daily at level ten can also help your financial situation, as the random reward bag has a pretty high chance of containing a Swiftness Potion, which tend to go for at least one gold if not more on most servers. For a level eighty-five that's nothing, but for a level ten who is trying to pay for his training with nothing at his disposal but a few silvers worth of quest rewards, getting a whole gold or more from a simple daily is a nice boost.
The one negative thing I see about this new fishing daily is that it won't hold the interest of anyone at the level cap once they've maxed out their fishing, because there is nothing interesting about the item rewards themselves. A gold for a Swiftness Potion is about the most you can hope for, which is absolutely not worth the time it takes to do the daily for a level eighty-five character. If you're still after a Weather-Beaten Fishing Hat or missing one of the croc pets from Crocolisks in the City, you'll have to do the fishing dailies in Shattrath and Dalaran, both of which are rather out of the way for max-level characters now. I kind of hope that Blizzard will add a new max-level fishing daily somewhere in a later content patch.
The cooking daily also suffers from the problem of trying to appeal to both levellers and max-level characters at the same time. Mind you, I never had a lot of problems levelling cooking before, but with how fast and smoothly you zoom through the low levels these days, it's probably harder because you don't get to see as many zones with vendors selling recipes and won't kill as many random mobs for useful meat drops. There have also always been certain level ranges where it's harder to skill up than in others (250-300 for me, mostly). Either way, getting extra skill-ups from doing the daily helps.
However, the Chef's Awards for completing the daily are decidedly "meh" for low-level characters, as all the recipes that you can buy with them require a cooking skill of at least 450. While cooking skill isn't restricted by character level anymore, it's unlikely that you'll be far ahead of the "intended" skill range on your average alt, especially with the aforementioned factors making levelling cooking something that might not happen as easily on its own anymore. You can't save up awards for later either as they are capped out at the very low number of ten. You can buy the recipes early and build a stockpile in your bank for later, but that's not really ideal either. Your only alternative way to spend them is the Crate of Tasty Meat, either to stockpile meat instead of recipes, or to sell the contents for gold.
I don't want to scoff at that because it's certainly got its uses... but I just find it odd that the quest itself is very obviously designed for low-levels (as you won't face anything worse than a level 11 thief) but the rewards are very much aimed at high levels. As a result, putting their Chef's Awards to good use is a clunky process for lowbies, while characters at max level get encouraged to repeat a completely trivial level ten quest over and over for weeks in order to gather all the new cooking recipes. It just doesn't sit quite right with me.
In summary, I enjoy both of the new profession dailies and I think that they are fun as well as a great help when it comes to skilling up your secondary professions. However, I also think that trying to aim them at low-levels and characters at the level cap at the same time wasn't really the best idea ever and I would have preferred it if they had introduced separate dailies for different level ranges. Maybe in the next big patch.