Executive summary: I feel that the introduction is poor, and whatever Blizzard's goal is on the matter it is likely to be undermined by basic player psychology.
I am an officer and "raid leader" for my guild (see tag). I put raid leader in quotes because my guild is hardly a raiding guild -- we're so casual that the grass in Firelands has time to grow between our "progression" boss kills. I am an elite player in absolutely no way, shape, form, or manner, and from what I can tell my guild will by necessity have to treat epic gems as if they do not exist.
But I'm not writing this post to whine about myself. Instead, I think that the epic gem introduction is ultimately bad for everybody.
Ultimately, I'm arguing from the position that Blizzard has deliberately introduced epic gems in a manner in which they will remain extremely scarce for a long time. As implemented now, the system is a serious throwback to the Burning Crusade, and it ignores the lessons learned from Lich King about the ultimate benefits of gear democratization.
Now, I am basing this post on the assumption that the current source of epic gems -- soley the Dragon Soul -- is going to remain the status quo for some time. Blizzard could make this entire post obsolete tomorrow by raining epic gems from the sky, or whatever.
Epic Gems are Bad for Jewelcrafters:
Right now, Jewelcrafters bear the entire burden of turning epic gems from their raw form into useful cuts. That's the nature of Jewelcrafting, of course, but the traditional "economic" model is that Jewelcrafters should also have the inside track on obtaining those raw gems, namely by prospecting ore. This acts as a kind of compensation for the daily-quest grind for the patterns.
This bargain is subverted with the current epic gem model; jewelcrafters have no better source of gems than anybody else. This means that jewelcrafters are stuck in the position of providing an essential service to the community (that of cutting the gems), but they have no control over the actual bottleneck (the raw gems themselves). It's not the biggest deal, but it's going to put a lot of pressure on jewelcrafters.
The best alternative would probably for jewelcrafters to move to a `commission' model for cuts, but the true development of that is going to be hurt by the raid-centric drops. Just as in BC, progression raiders who are accumulating the most gems will also likely have in-house jewelcrafters to do the cuts. Also, this gives said raid guilds a natural vertical monopoly: they're likely to be the best source of gems at auction, but they have no incentive to provide uncuts when they can do the cut and take the value-add themselves.
Introduction of alchemy transmutes for epic gems and a JC-related transmute (Fire Prism-style) will only mitigate this somewhat. It still ultimately results in jewelcrafters not being the best source of their own materials.
Epic Gems are Bad for non-Blacksmiths:
I'm only going to touch on this point because other threads on the front page have touched on it, but I will summarise.
In the current model a fully-geared Blacksmith is going to get +100 to her main stat from the profession perk (2 sockets), but other professions only provide a net of +80. If this remains unadjusted, it will make blacksmithing the clearly superior raiding profession. If this is adjusted to +100, then while epic gems remain scarce the other professions will have the bonus (+100 for no/little/not scarce cost! Kermit Yayayay!)
Personally, I do not care too much about a net difference of 20 stats, but that is one of the things that makes me super-casual-for-life.
[continued, next post]