I posed this question to my guild. We're getting close to the release of Patch 3.3, and I'm fairly excited at the chance to go head to head with The Lich King. We've worked hard to become a guild that can role play as well as we raid, with our focus being on 10 person progression since our desire as a guild was not to field the number of members necessary to run 25s. I have been leading our raids since the beginning of Wrath, and when Icecrown does open its gates, we'll be there waiting.
I asked in our forums what your character's personal reason for defeating the Lich King was. As a player, I feel I have some vested interest in this because I've played Warcraft III where I literally played as and watched Arthas seal his fate as he climbed the Frozen Throne. This is a culmination of those events I played through several years ago and I'm eager to see what happens. Will he die? Will he be redeemed? Will the Burning Legion show up again? He was their creation after all. I'm extremely excited to play through the dungeon quests, to see the storyline for so many characters progress, and to deal with the aftermath and how that will affect my own characters, the guild, and the world at large.
Elionene has waged war on the Legion ever since her father died at My. Hyjal. She sees the Lich King as an extension of the Legion and has vowed to remove this threat from the world. She also happens to be in the position of a leader of a small group of adventurers that share her sentiments, though they all have their own reasons. Salthier is concerned with the rifts this war is placing between the Horde and Alliance. It took their combined might to stop Archimonde. Can they succeed against Arthas divided?
I bet there are some good stories out there. Maybe you don't want to kill the Lich King. Maybe you're fine with him. Maybe you want to be him. Maybe you'll do whatever grants you the biggest profit, monetary or otherwise. Maybe you're already bent on future threats, and are willing to leave the Lich King to others.
I've read some rumors about what is supposed to happen with the defeat of Arthas. I'm still looking forward to seeing it first hand. Ulduar was hard to figure in, and sort of a let down at the end. We killed (or did we?) Yogg-Saron, but what effect did that have on the world? He wasn't even out of his prison yet when we got to him, so why was he such a big threat? We didn't have the Alliance or the Horde backing us. We just went along to help out Brann.
Then the Coliseum came with Tirion's grandiose plans to take the winners to Icecrown. Elionene still holds that this is foolishness, but she goes along with it because it is what is expected of her and her friends to reach the gates of Icecrown. And it's also the only way to curry favor with the Silver Covenant, who she aspires to be exalted with. She does what she must.
Now we're closer than ever to Icecrown, and this time, the battles should mean something. But what does it mean for you? Why do you want to kill the Lich King?