The biggest fear seems to be that players who have never raided before will start walking around in Ulduar- or even Coliseum-level gear, and they'll get invited to raids based on their gear, only to find that they're clueless about what to do. But I like Arioch's point there: does that mean we don't have clueless raiders now? Of course we do -- the gear you're wearing doesn't say anything about what you've done now, and it'll say even less after the patch. Players are already requiring achievements, and even that doesn't necessarily guarantee you're a good player.
Will there be bad PuGs after the patch? Of course, and there are bad PuGs now, too. But this is definitely a helpful change for anyone with alts, and while yes, it will allow non-raiders to get better gear, and it will probably bring raiders back into Heroics more often, it still won't affect those who are raiding at the highest levels. They'll still get the best gear earlier than everyone else, so if that's what's important to them, they've got nothing to complain about.
Patch 3.2 will bring about a new 5, 10, and 25 man instance to WoW, and usher in a new 40-man battleground called the Isle of Conquest. WoW.com will have you covered every step of the way, from extensive PTR coverage through the official live release. Check out WoW.com's Guide to Patch 3.2 for all the latest!