As I'm not currently raiding, I didn't mention the Icecrown Citadel buff up to now. Blizzard had already in previous expansions made characters stronger and nerfed raid dungeons with time, so that at the end of an expansion people could visit raid dungeons they had been previously been unable to beat. But the ICC buff is the first time this mechanism is formalized. It started as a 5% buff on just about anything (health, healing, damage), and with time will grow to a 30% buff. Rahana from Blueberry Totem has a thoughtful post with a more detailed description and comments.
What I found most interesting is Rahana's report on the discussion going on in her guild about whether or not to use the buff. It is another of these cases where on the one hand people are complaining that the buff makes the raid too easy, but on the other hand raid groups don't want to turn the buff off (which they could), because it feels like raiding with one hand tied behind your back.
I guess I don't have the right achiever mindset, because that sort of discussion is completely incomprehensible to me. I would think that having selectable difficulty options is always a good thing. Want challenge? Play without buff! Want a tourist raid to just say hi to Arthas? Play with a 30% buff in a few months! But that personal view of challenge comes from me not caring at all what other guilds on the server are doing. Meanwhile the discussion in Rahana's guild is about whether they should "gimp our progress relative to other guilds" or the danger that "it leaks out we did it without the buff, we are definitely going to be called names and dragged through trade channel for being elitist epeen no-lifers who have to brag about their pixel achievements". Because they care so much what the other players in other guilds think about them, guilds feel obliged to use the buff, while simultaneously complaining about it all the time. Or they are just using that as an excuse, because they are secretly relieved to not have to wipe so much to beat Icecrown.