WoW Insider has a concise summary of the self-only crafting profession perks in wrath. To sum up, the devs felt that BoP epic profession gear encouraged players to take professions they didn't like. (It also led top end guilds to mandate that everyone take up Leatherworking in order to spam drums.) Nowadays, all your crafted gear is BoE and crafters get some self-only enchant-like perk. Depending on which trade you're working on, that's either a small bonus to a gear slot that can't be enhanced by any other means (belts, rings) or a larger bonus to a slot that can be enhanced by other means (shoulders, bracers, gloves).
Does your profession still do what it did?
My mage is currently a Shadoweave tailor, a specialty I picked up for the infamous Frozen Shadoweave set (now known as Shadow's Embrace). The set was very good at what it did - frost and shadow damage (a combo deliberately chosen because no class deals both) - but bad in other ways. The set devoted all of its stats to pure damage, and (until patch 3.0.2) received an additional bonus to that damage for being restricted to specific schools. This meant that players had to go several tiers above the set in order to find meaningful upgrades. The Shadoweave set, and the other tailoring sets, also presented a problem because they are specific to a damage type, meaning that they become useless to the crafter upon a respec.
Well, in the new era, it appears that the sole benefit of your tailoring specialty is an economic choice on which cloth you want more of. The new version of Shadoweave makes a pair of items that offer spell hit, and is needed for the 22 slot bag recipe (along with the third edition of Mooncloth). However, the former point is moot because you can equip whichever of the others you want (Spellfire produces spell haste gear, and Mooncloth produces gear with spirit), and you don't even need to be a tailor anymore. That is a minor disappointment if you went to the trouble of leveling tailoring solely because you wanted to make your own gear, when now all you get for your trouble is a cloak enchant you may or may not want, cheaper spellthread for your pants, and a rug.
If you are a Spellfire tailor at this point, you might be considering a specialty respec, as it is not needed for generic bags and will probably see a smaller market. Then again, things could change. Alchemy really wasn't all that useful as of patch 2.1, when I dropped it from my mage. Nowadays it offers a competitive trinket and increased benefit from potions/elixirs. Perhaps you'll drop Spellfire, or even Tailoring entirely, and then Blizzard will add something nifty down the line and you'll be sorry. Change and innovation can be good but this kind of uncertainty is less so.
Will changing the perks even work to stop min-maxing?
No. The Elitist Jerks thread on Wrath mages is quick to inform you that "Mining, Skinning, Tailoring, Engineering are currently not competitive options for Mage DPS."
Money makes the world go round
The epic crafted gear that formerly made a profession perk are now BOE's, meaning that anyone can and probably will buy them at the AH. Indeed, unless you really care about the increment between your profession enchant and the next best alternative, professions are now less necessary than they were before Wrath. But this isn't the only change with BOE's. Tobold has some commentary on BOE epic raid boss loot. These items may or may not cause a loot distribution nightmare for raid leaders, but they're also part of a trend - Blizzard apparently wants players to be able to buy epic upgrades for cash.
There are some upsides to this plan. Everyone can get cash, regardless of their raid availabilty. Cash is gained one copper at a time, so players can progress as quickly or as slowly as they're willing to. Cash is gained from most activities in the game, even including leveling low level alts (at least, if you can resist the urge to spoil your lowbies with twinked leveling goodies ;)), so no one is forced to do any specific content. AH fees on crafted goods will help sink cash out of the in-game economy. And, finally, cash is not soulbound, meaning that you can rapidly gear up an alt, or even a friend's main, and have them ready for at least the entry level of Wrath raids.
That last point, though, is also a downside. The gold sellers of the world are rejoicing to see their product featured so prominently yet again - sure, the materials to power level a profession cost in-game money that you could choose to buy off a gold seller, but that's a less direct process than seeing a finished item on the AH for X amount, which a spammer claims they will sell you for Y dollars. The ability to sell raid drops for in-game cash also opens the door for ninja looting and various other scammery. Let's just say that I wouldn't advise you to join and PUG's that aren't run by people you personally trust.
These changes appear to be here to stay - Blizzard actually experimented with BOE raid loot for the two Outland world bosses a few patches back, and apparently liked the results. As I said, it's probably a good deal if you don't care at all about crafting, as you'll be less penalized for not doing any. (Indeed, as an enchanter, one can argue that I can continue to get milage out of my existing ring enchants for a while to come, lessening any pressure to level the profession for upgraded ones.) If you care greatly about crafting, you're probably going to level all your professions anyway, though this change may make you regret choices you made the last time around.
In the middle of the road, though, it seems like the shift to crafting is a net downside. Fewer incentives, and, in some cases, incentives available at lower skill levels compared to their TBC counterparts, leaves less to make crafting worth your while. Perhaps Blizzard will use the relatively empty space just before the newly increased crafting caps to introduce some crafting progression later in the expansion cycle. Perhaps the crafters that are left in the economy will find more profit potential due to decreased competition. In the mean time, though, it feels like the AH's gain is crafting's loss.