"Every mage has a horrible matchup against the Tuggluk-style dwarf rager warrior if played properly."

But every Tuggluk-style dwarf rager warrior gets stuck in quicksand because they can't fly, can't recall or teleport out of bad situations before they happen, can be summoned into a locked room, etc. There are always weaknesses to the Well-Played Character of the Month (tm). Deathblow is overpowered, preps are too plentiful, centurions are overpowered, bash is overpowered. When everything is overpowered, generally that means the game is a well-balanced version of rock, paper, scissors, but on crack, where each possible combination is strong and weak against various other possible combinations.

My point is that when you're on the receiving end of a particularly good character, especially when played by a particularly good player, it's easy to jump to the conclusion that the situation is imbalanced. And if some class/cabal/race combos work better against a particular class, you can just about guarantee that there's another class that will tear said "good combo" a new one. The key is to avoid fighting the classes you're weak against and hunt down the ones you're strong against.

As for deathblow being too strong, that argument has been around forever. The counter is that ragers have it tough: no preps, no flying, no magic, no nothing. I don't know that you're going to get deathblow dropped any in power...my ragers had more kills, but more deaths, per played hour than any other class/cabal I have played. More deadly, yes, but more dead too.

Anyway, I know it's frustrating to get killed by seemingly one-trick ponies. But if it works, and you keep falling to it, why should they change? Personally, I dislike wrath-spamming paladins, but if that's the quickest way to get as much damage out in as little time as possible, it's legit. Same with bashing giants. Same with pincering axe specs, cranialing mace specs, hurling dagger specs, impaling spear specs, sleeping necros, rotting shamans, assassinating assasins, binding binder thiefs, flyto/murder air shifters, entwining whip specs, deathblowing rager berserkers, etc etc. Everyone's got a niche, some special ability that defines their class and makes it powerful. But every character has a weakness, too.