Tirion did kick LK's ass, when he was finished toying with the "group of unknown heroes"..
Azshara wields he powers of an elemental lord (Neptulon), which she have captured. LK is not nearly as powerfull as any of the elemental lords (yes yes, two of them are dead now)...
Lei Shen, like Azshara, and Lich King, and Sargaras, and Medivh and any other character in WoW lore, is exactly as powerful as the story needs them to be to tell a (or the) story, nothing more. They're characters, they don't exist outside of the story. They don't have "power levels", they have some narrative description of their powers but the narrative is the story within which we are playing and participating.
No one asks these questions about the level 87 yaks you fight in Kun Lai summit and yet the same truth applies. Characters in games and stories have whatever power is necessary to make the game or the story function, no more, no less. There is no independent measurement of their power because they do not exist. Their powers are loosely defined and then refined by the authors and designers, which is why these sorts of inquiries do nothing but result in endless arguments. There is no independent way to evaluate the claims of power, there is only the way their "power" is defined and depicted in the story.
Lei Shen is exactly as powerful as it takes for him to put up a good fight but ultimately lose, just like Lich King, just like C'Thun, just like every other being of immense and monstrous power with which we have battled.
I normally never delve into these lore threads, but when someone asks or talks about how "strong" someone is, what exactly do they mean? Do they require 40 players to bring them down? 25? 10? :P
I mean really though, I never understood the argument of a character being "powerful" primarily because... while lore might portray them to be powerful... they still die, and for game purposes, retreating before you die, is dying.
To really place him on a power scale you have to place the adventurers (players) somewhere on a power scale too. It took 10/25 level 80s and a super paladin to take down Arthas. Took 10/25 level 90s to take down Lei-Shen. Also would have to put that super paladin on a power scale, I mean, all he really did in the fight was break an evil sword with a holy sword.
Did players gain that much power lore-wise after we defeated the king of the undead, a twilight dragon, a cult of C'thun, the family of Deathwing, the elemental lord of wind, elemental lord of fire, Deathwing his followers, a mogu attack force, a bug attack force, and corruption in the terrace of endless spring? I'm gonna lean on the side of yes...we got stronger. So yes...Lei-Shen is most likely stronger than LK. And cant really put Lei-Shen any higher in power, because all of patch 5.0-5.3 was all about the trolls working to get Lei-shen to full power, and he was when he was killed.
He was strong enough to be a threat but not strong enough to stay one.
"Terror, darkness, power? The Forsaken crave not these things; the Forsaken ARE these things."
I say much more weaker than the Lich King. After all the Lich King had the power to ressurect the Titan Galakrond under his command. Who's to say he can't ressurect any other falled Titan? Personally I believe that the difference between the Lich King and the rest is that the Lich King's power has unlimited potential while the rest are limited.
The only indication of Azshara's power to go by is that tabletop Warcraft RPG.
LK took the entire might of both the alliance and the horde put together over the entire expansion, and he still would've defeated everyone if not for the deus ex machina of the final part of that fight (and really should've poured out of northrend at the end of WC3 to conquer all of azeroth, but that's neither here nor there). He wouldn't even have lost if they hadn't gone out of their way to contrive the situation so that he'd lose. The same could be said for Deathwing, who could've easily destroyed pretty much everyone in no time at all, but decided to chill out for a bit and wait for us to come kill him instead.
Lei Shen by comparison, took the combined efforts of....... deathwing's little baby whelp and some pandaren who couldn't even resist the sha, and that's while he had the aid of all those trolls that came out of nowhere. Yeah, I'm sure he was totally undefeated before he "died of old age", then was easily defeated by a bunch of randoms who barely even knew who he was the first time that he fought anyone after coming back. Sounds more like history is written by the victors to me.
Lei Shen is nothing. He's like a roadbump leading up to Garrosh, who would himself be nothing relative to the Lich King.
One thing I've wondered since the introduction of the Thunder King is if we even fight him at his best.
Now the reason I wonder is because he died of old age and was subsequently resurrected, did that restore him to his absolute full power or around about whatever power he still had (whether it diminished or not due to his older age) when he died.
Either way I think it speaks volumes that he ruled what seemed to be a meritocratic empire and died of old age instead of being usurped.
I think some kind of epic Deadliest Warrior-style mock up CGI or just animated fight between Lei Shen and the Lich King would be amazing.
This is an utterly meaningless statement: "see it from a 'lore' perspective"? You have no idea what the physics of this world is or what defines these powers. There is nothing other than the story. The entire discussion of "who is stronger" is a meaningless discussion because the characters do not exist and do not have specifically defined abilities.
The derp is on you for pretending made-up characters in a story that are introduced as protagonists and antagonists for the purposes of advancing a plot line can be treated as "real beings" and have their abilities compared. Its a meaningless exercise because at any given moment their powers can be altered and redefined by the authors.