Daelo, on the WoW Forums:
After each region's maintenance this week, raids will no longer lose attempts on wipes in Normal mode for Professor Putricide, Blood-Queen Lana'thel, Sindragosa, and the Lich King. There will still be limited attempts in Heroic mode.
We will continue to monitor developments in Icecrown Citadel in the future, especially since the Heroic difficulty has been unlocked by a significant number of raids.
There is a saying that generals are always trying to fight the last war. In a sense, so is Blizzard. The big problem in Trial of the Crusader was that the gap between normal and heroic was too large.
To fix that problem in ICC--to create more of a spread between the Gentry guilds, but still have many guilds eventually complete the instance--Blizzard added normal-mode attempt limits for the end bosses. I think the idea was that the normal-mode attempt limits would slow down Gentry guilds, but not really impede Aristocracy and Royalty guilds.
However, ICC turned out to be reasonably difficult. The attempt limit isn't what's holding back Gentry guilds. And the Royalty guilds are going out of their way to evade the normal mode limits, because they can't afford to fall behind on hard modes. Several edge guilds are doing alt runs of ICC first. I understand that Paragon, which got the world first Arthas kill, took this path.
So Blizzard removes the limit for Gentry guilds, and is relying on natural difficulty of the fights and the eventual Faction Leader buff to spread out the guilds.
What will be interesting to see is how Blizzard reacts to the creation of alt teams to evade time and attempt limits. I'm not really sure what they could do, other than excessive attunement chains. But if it is hard to attune alts, it is also hard to attune trials and new characters, and that has its own pitfalls.
Perhaps Blizzard will just start creating impossible fights, with a built in buff timer like the Faction Leader buff timer, and let the best guilds wipe until the buff stacks just high enough to clear the bar. Like a high jump bar slowly being lowered until someone can just clear it. Then the bar keeps going down so the rest of us can experience the fight.