First I want to thank Blizzard for archeology! I loved it, so everything that follows will be biased. I am grateful that this remained in the game, despite the removal of the original "Path of Titans" character customization.
The storytelling with artifacts is such a brilliant idea! Those achievements for archeology added real value to the profession, and added a lot of lore to the game world. Real archeology is not about finding obsolete and rotten things, but about uncovering stories. You might consider taking this to the next level with, for example, a rare artifact which starts a quest, or a set of common artifacts that can be combined to form a quest-starting item. This would lead to obvious tie-ins with the Explorer's League, or The Reliquary, respectively. So many possibilities! :-) And quests would avoid spoilers in the list of possible achievements.
But not everything is nice and dandy with archeology. It is not really for characters below level 70 due to the overhead of travel. This is not necessarily bad, because archeology is the first true "Elder Game" in WoW (i.e. game content that brings high level characters back to low level areas, but with a completely new view on the world). But archeology does create yet more pressure to obtain fast flying ... maybe Mists of Pandaria will inflate gold to the point where the cost of fast flying becomes trivial?
Then there is the unfortunate issue of bottability. I couldn't believe it when I first heard it, but apparently not everyone likes archeology as much as I do. I guess some players found the iLvl 359 gear just too compelling. The obvious fix would be to introduce archeology gear gradually over the duration of an expansion, and always have it be a tad weaker than current raiding tier. Let it be for secondary chars, or for catching up. Let archeology be optional rather than mandatory.
And then the biggie: bag space. Two dozen rare artifacts to fill up bag slots, oh my! This is the one detail of archeology that is truly evil. :-) Blizzard, you must find a better way to store all those collectible curios. Their number will only increase through the eras. You did it for mounts and companion pets already, you're going to do it for tabards "soon(TM)". Please give us a stash for the collectibles, too.
Nevertheless, archeology is a great addition to the game! In my not so humble opinion it is the first of the secondary professions that adds real value. But of course this is a matter of taste. Still, I hope Blizzard will build on that and expand archeology further as the game evolves.