Let me try to narrow this question a bit.

Try to list combos that a player with extensive area/prep knowledge (but mediocre skill) could exploit in order to kill (certain) characters played by more experienced players who take every reasonable precaution to avoid dying.

Combos where you basically just "turn the crank" and out comes PKs. You may not match up well against everybody, but against some subset of opponents it's like shooting fish in a barrel.

* Snare/enlarge/haste/waylay/bearcharge on a cloud ranger.

* Sleep/summon/etc. on a necro.

* Sleep/maledict/etc. + vault on a Anti-Paladin.

* Bash, bash, warcry, flurry on a giant warrior + relevant legacy.

* Nightreaver bard.

* Assassinate.

* Improved invis + quicksand.

* Shalsad, e.g. wasp + dire wolf + bloody shackles.

* Scroll-happy binder.

Anybody feel these are so "gross" in certain scenarios that maybe they should be changed somehow? Having played a couple of those, or near enough, there were some fights where I thought to myself, "This guy might as well roll over and die, because he has NO chance to survive this." And, significantly, this near-surety-of-death wasn't due to any particular skill on my part. It was just the interaction of my combo with my opponent's.