There are three enchanting activities: auction house work, tip work, and DEing in instances. The second group had really no changes at all. People bring mats and give them a pittance of gold, just as usual. The third group lost control of their profession and their pseudo-farming had been wrecked by the crashed mat prices. The first group is me.
My profession remains safely in my complete control. I don't sell WotLK mats. I buy them. So I benefit from cheap mats. I can create scrolls with less investment risk and prices didn't go down too much. Basically I gained profits at the cost of other enchanters.
Some have tried to claim that this is a spreading of the wealth. Bullshit. Did non-enchanters gain? Probably. But how much really? Before they got the vendor price of 4-8g for blues and 10-15g for purples (this is armor, not weapons). Now they get shards worth 6-8g and abyssals worth 25g. On weapons they're actually losing gold if they hit DE, but they're so convinced that shards are great and wonderful that they pick it anyway. On armor the gain is marginal. Only on armor DE do they gain much; about 15g per instance (not counting ToC and ICC), averaged among four people, and wow, that's pretty trivial. 3g average; less than is lost by the people who 'speed run' when they really mean 'don't loot corpses and lose a dozen gold in coin and vendor trash per instance'. In other words, the spreading out of mats didn't do much.
The lower mat cost has a greater effect, especially for those who would buy mats and tip enchanters. These people they gained quite a bit actually. They still give trivial tips and now they pay even less for mats. What a great change, it has enriched the jackasses who tip 5g for blade ward.
The 'gatherer' enchanters who go out and run instances and get their profession stolen, the ones who make the enchanting market possible, they lose. My most convenient source of mats is by playing my non-enchanting alts in instances and getting cheap mats by hijacking my fellow enchanters. My cheapest source is the AH where enchanters and non-enchanters furiously scramble to sell the flood of mats, undercutting each other to the point that dust is 1/4 what it used to be, with other mats having less dramatic, but still significant price drops.
The biggest gain was for the 'crafter' enchanters. But my enchanter who sits in the AH all day and makes scrolls at a 25-100% markup, he's doing just fine. I'm not going to spew that crap about "lol it's just clicking a button" because that's stupid and ignores the cost of leveling and other stuffs. But with cheap mats and no deposit, it's a nearly riskless activity. My JC goes through 1.5g deposits constantly; losing some, getting some back. My enchanter never loses a deposit because scrolls have none. He can just keep posting over and over and lose nothing but a few seconds. The lack of a deposit also keeps up prices.
Clearly my enchanter provides a valuable service. But so do the 'gatherer' enchanters and they get absolutely nothing. They get as many mats as before, but with much lower sell prices. They're losing an incentive to run instances.
I predict two competing forces that could affect my enchanter's profits. Fewer enchanters running mean prices go up along with my risk, and away go my profits. However fewer enchanters could also mean the characters going idle or switching professions, which means less competition in the scroll market.
The net effect of the DE change was to spread some gold away from enchanting as a profession, but within the profession there is a dramatic reversal, an extreme concentration of the wealth.
Off-Topic: Questions I have no Answer to
1 hour ago