Lord Ahune is huge! I did a few runs with him on regular and got him down on heroic. I ran it this first night a total 11 times. I think we didn't kill him 3 of those times. When new members were learning the fight was when we had the most trouble.
I really liked the animation. We did have members have to turn down their graphics. The adds, the frost spikes, the AoEs, and ... well just everything made this fight laggy for some.
Both our enchanters had the new Enchant Weapon - Deathfrost drop. So I am hoping that all the drops will be cycled though. Because we all know that everyone who can equip one will want a Frostscythe of Lord Ahune.
In normal mode you don't have to reset the instance to summon Ahune. Which is convenient so you don't have to reclear adds or have the five instances an hour rule to worry about. Once the chest with the loot is empty, it will despawn and the summoning shard reappears.
For Heroic, we had a Pally tank, Shaman healer, Rogue, Mage, and Warlock. You can only do Slave Pens on Heroic once. When you kill Ahune you get a badge of justice and are saved to the instance. The adds and the frost spikes on the ground come faster. I am sure the mobs and boss have more heath also. Having two AoE was an asset.
I found this was a very mana intensive fight. Healers had to watch mana usage. Our mage said he used three pots a fight. I was looking at an OOM imp. So I potted too.
Loot is NOT disenchantable. This is exactly the same as the Headless Horseman. This time though there is no fun repeatable use items like the brooms. I do have the say the Huge Snowballs ... live up to their name.
Absolutely harder then the Headless Horseman. But then again ... I helped kill the Headless Horseman sixty gazillion times. So my memory maybe fuzzy on how hard the fight was. Ask me again in a few days.