I got a chance to lead a raiding force from my guild into Karazhan last week. It went really well. I was very pleased to find fight after fight that managed to rely on coordination and communication, as opposed to old style raiding which relied on how fast can mages, priests, paladins and druids spam their respective cleanse spells. I started out with a conservative group, which to me means a group that's heavy on heals at the expense of damage dealers. This makes the fights take longer, which means the fights are a lot slower. When things begin to devolve, we can all see very clearly what's wrong with our tactics and modify them during the fight or at worst after the fight. This works great up to the Curator, where if the group doesn't have enough damage dealers then the event becomes very difficult.
The instance is pretty. Very pretty. The fights are engaging and require adjustments for class balance, which is great because many of the fights in "Vanilla WoW" had very hard class requirements for crowd control. As it is we can do most events with one priest and one or more paladins. I actually prefer a shadow priest for the Vampiric Embrace goodness, which helps out the paladins a lot with their mana usage on long heal fights as well as improving our raid's damage output. Even with the priest nerfs that went in, Shadow is still a very viable raid spec. In addition I've had a paladin play offtank with great results. I haven't had any druid tanks yet, but only because the scheduling hasn't worked out yet. In other words, this is a great small-guild instance, it only requires 10, you need adequate healing and tanking which can be supplied by multiple classes, and you need adequate DPS. The gear checks aren't even horrible, a group that's geared with nice blues from Shadow Labyrinths, Steamvaults, and the Tempest Keep instances will do very well here.
So how are you doing in Karazhan? Do you have any stories to tell?