Patch 2.4 was the result of a few things going not-quite-right with The Burning Crusade. First, Wrath of the Lich King was taking longer than their original time tables said they would, especially considering how rapidly they put out Burning Crusade's raid content. They front-loaded all of it. Black Temple, the raid zone that was supposed to be the pinnacle of 25-man raiding in BC, came out in patch 2.1 just a few months after the launch of the expansion. It was almost a full year between the release of Black Temple and the release of Sunwell Plateau. That's a pretty long time with no new 25 man content. If they didn't do Patch 2.4's raid, it would have been almost a year and a half between Black Temple and Wrath of the Lich King.
Another issue is that, given the theme of the expansion (The Burning Crusade), ending on a raid that didn't have anything at all to do with the Burning Crusade is somewhat silly. Sure, Illidan had pet demons, but he wasn't actually a part of the Burning Legion anymore, which is what the Crusade is named for. It's somewhat like if Wrath of the Lich King gave us Yogg-Saron last and skipped Arthas. Sure, Yogg-Saron was a villain, and a pretty big one! Entire zones dedicated to his influence! But he wasn't in the title of the game. As much as they hyped Illidan, the title of the expansion simply wasn't about him. It was about the Burning Legion.
Wrath of the Lich King feels much more on-pace, though we were spoiled by how much raid content was available at launch with The Burning Crusade. The Lich King will definitely be in patch 3.3 and will probably be the final raid boss of Wrath. If he's not, it's because their next expansion is taking longer than they'd hoped, and the filler content (the potential patch 3.4) will be a good thing for us players because it'll give us something to do while we wait.
"Is there a good guide anywhere to the differences between the Ulduar-10 and Ulduar-25 encounters? I usually raid with a 10-man, but we're teaming up with a few other 10-man teams this week while a bunch of our teammates are taking vacations. It'd be really helpful to find a list of what's different."
As was mentioned in the comments yesterday, Wowwiki is a pretty good resource for this. If there are significant differences, it'll be noted on the boss's tactics page. Most of the differences between 10 and 25 man come down to numbers, rather than new abilities. The 25 man version makes healing and damage requirements much tighter, as in your tank is much more likely to get 2-shot in Ulduar 25 than Ulduar 10 and there'll be significantly larger amounts of environmental damage going around. New abilities between Normal and Heroic are few and far between.
"Just courious about RaF... if I want to recruit myself, i.e. buy another account for myself, does that mean that I also have to buy all new games as well, and then own two of every game? Or can I have two accounts on the same game?"
You need an authentication code/CD-Key for each account, and you get those buy buying the base game and expansions. So... yes, you need two copies of everything if you want two accounts. If you don't want the actual boxes laying around your house, remember that you can get the original game and the expansions on the Blizzard Store digitally. If you have a Battle.net account, you can attach both accounts to one login and have all of your game information stored on Battle.net. It's actually a pretty convenient service for multiboxers!
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