Is this one of those things were you mask complaints or criticism behind parody? Usually people chose sneaky rogue types because either: Beef-cake warriors get snuffed by the villain of the week to prove the strength of said villain of the week, or old men with magic sticks get rendered useless to prove the toughness of the villain of the week. If people aren't getting worfed, their attacks are getting nerfed. You have to fight smart and cunning when brutal efficiency or your years of magical expertise gets countered for the sake of plot. Of course, specializing into being just the warrior/rogue/wizard is getting phased out for more skill versatility, or at least the ability to use your same play style in different flavors. 

There will come a point where Malakaus's "Hit them with everything you got" style won't work... Because he's using physical weapons. Eventually he'll use magical weapons, which still amount to "Hit them with everything you got" but with magic instead of axes. That's what assassins and the like are often known for: have no restriction to their tools or methods beyond what they can prepare. They can stab you in the back or fry you with lightning, neither one of them would be unexpected. But to see a bonefide warrior slinging ice spells, or a mage in the thick of battle swinging a maul in heavy armor? You'd think either they were a made warrior or mage, or just multiclassing.

But I guess that's the other issue with rogue types too, neh? By taking the middle ground, they have the potential to be better than either classes if they lack restriction. The best warrior won't match up to the best rogue if he's just as good as a warrior AND is also just as good of a mage as the master wizard. Sneaky assassin types often can somehow defeat armored knights in strait up combat, somehow finding ways past their armor (If they don't simply stab through the armor) or able to close the distance with mages or escape their foresight before the mage can pull off their spells. It's probably why everyone has Perception as a class skill; to have something that would allow them to counter ambushes and sneak attacks and take away a rogues most devastating ability: To hit first. And when everyone starts playing rocket tag, he who strikes first wins first.