First some background.
I sent a pm message to kylenne explaining why I felt that Kael'thas's fall into darkness was actually pretty logical a few weeks ago. Basically I stated that when your exposed to a substance that warps your brain and erodes morality it's not far fetched, and Kael thas was always one of those guys who'd do whatever it took, even if it was stupid and reckless (lets be honest, engorging fel energy is stupid and reckless. look at the orcs). She responded by blocking me from ever sending pms (something that no one else has done even on the rare occasions that things have gotten to politics or heated debates.) Anyway, now she's on live journal complaining that I was defending an "ablist" interpretation and defending bastardization. While I doubt she'll see this, I still feel obligated to express just how petty her "ohh wahhh you dared offer a different interpretation you're a meanie" spiel is, and why I still stand by my belief that kael's descent into madness was well done. I mean when I got a stronger reaction than most other people I've encountered on the internet (which is many) than I kind of have to marvel at it, and to be honest I haven't really had a lot to post about so I might as well use this. I'd reproduce the part of the message that got sent, but evidently the block she had means I can't access the pm.
Anyway, Kael'thas made it clear he would do WHATEVER it took to help his people. What's the expression......Oh yeah the road to hell is paved with good intentions. Often times villains do actions they believe to be for the greater good. While it is true that Kael'thas was dealt a crappy hand, he still made it clear that if a method came that he thought could help his people arose, he'd take it. THis left it open for him doing morally reprehensible acts if he thought it would help his people. Now lets consider the following.
1.) Illidan promised to help him avenge Quel'thals by killing Arthas and destroying the frozen throne. Illidan failed, and the shock of loosing it all, facing the wrath of kil'jaeden and getting his butt kicked wouldn't have helped his low sanity (he freely admitted as much to Maeiv, and I doubt the skull of Gul'dan helped his sanity; getting your assed handed to you in your moment of greatest triumph probably wouldn't either). Witnessing a potential savior fucking blow it would leave Kael wondering what options were available. Due to the lights failure I doubt he'd go back. Now Kil'jaeden's offering him something similar that may work...........Kael could easily go "Oh well desperate times desperate measures"
2.) The more you do horrible actions, the easier it becomes. It's called jumping off the slippery slope. As kael did more desperate actions it became easier to just say "oh it's for the greater good."
3.) Fel energy is actually corrupting, and was stated to be addictive. Kael'thas's brand was far more potent than the blood elves of azeroth and he was consuming in larger quantities. As quoted by a guy on TVTROPES, it's possible for a good decent woman to become so addicted it's possible she'd sell her children in child porn for the money needed for a fix.
4.) In the trailer for fury of the sun well we see a band of blood elves moving towards him (and their token jungle troll) and kill him (well it's implied anyway.) During the battle he said lines that implied he still cared. But now the people he's fighting to save have told him point blank "WE DON'T WANT YOU!!!! FUCK OFF!!!!" After he's done all this for them, they reject him. Now factor in the circumstances of his rebirth and the violence of his demise, and his minions saying he's been off since Delrissa brings him back Maybe he just thought that after his people rejected him only his followers were worthy of salvation and his people would need to be converted by force....... Maybe they mucked with him when bringing him back. There's plenty of possibilities. and 4 to 5 years happen off screen so we don't see the whole effect of his transition
I understand that some people like Kael'thas, but to react with the sheer amount of force and attitude she did shows that she is as immature as she claims me to be. While it is okay to have your views, one must be willing to concede that there is a possibility that they might be wrong, and that maybe the opposition has a case. I've debated politics and never been blocked like she has. Her friends responses of "kill him with fire for Kael" only show that they too do not tolerate dissent or the possibility that the direction they liked might not be the only alternative.
So in summary this guy from tvtropes sums up how I feel about Kael'thas.
"It's actually a fairly accurate discription; Kael's story is one of succumbing to addiction, plain and simple. It only looks like character derailment because a good four or five years of it take place off screen. But as someone who's grown up around drug addiction his whole life, this troper found Kael's development to make perfect sense. When you've seen a good, decent woman fall so far into addiction that she'll rent out her children for use in child porn just so she'll have money for a fix, the thought of a fantasy prince selling his people to the devil after years of abusing magic hardly seems far fetched."
Here's her reaction in a nutshell.
YOU BIG MEANIE HOW DARE YOU SAY THAT THE PATH I HATE MIGHT ACTUALLY BE LOGICAL!!! U R N FANBOY FOR KNAAKKKK!!!!!!