The problem is that all of the mentioned measures are very specific. As in, I can’t use them very often or the players get pissed. And you can’t very well have lava pop up in the middle of the dungeon very often, or avalanches, or teleporting monsters, etc.
The real problem is that we’ve got one puzzle solver, who always plays a mighty spellcaster (usually with every advantage/combo in the book plus several he devised himself). One guy who ignores the game except to randomly whip out his mega-specialist ability (and who swaps characters every few sessions). Two crazies who really don’t care but like to have long-winded but pointless conversations where they babble incoherently at the monsters/NPC’s. One guy who flies into berzerk rages (Him, not the character. Well, the character, too.) and destroys all evidence/clues to the next plot.
Basically, I can’t put in puzzles which will hold up puzzle solver for more than five minutes. He’s that good at solving them. He doesn’t need to be a Rogue because he simply comprehends how any trap can work, and takes measures to avoid any magical and nonmagical trap (seriously, he knows of which I speak). And he can solve puzzles faster than I can make them. If he does make a mistake, or someone actually finds a method of outsmarting or tracking him, he gets pissed at me. I refuse to enable his passive-aggression.
The other power-gamer will randomly whip out powers I’ve never seen before, usually some super-specialist can-opener ability. He refuses to show me his character sheet and swaps characters at the drop of a hat. He basically uses our friendship as a tool to manipulate me. I refuse to be manipulated, so I won’t run for him.
I can’t put in anything subtle or which involves diplomacy or discretion, because the two loons wreck it.
I can’t run any game at all because the berzerk loon destroys any plot or clues, attacks anything which comes within reach (including, on one occaisions, the Pope), insists on playing machine-gun wielding marines in every setting, including DnD, and gets mad at me for either challenging him or not challenging him. Yes, he actually gets mad if I he’s in any actual danger and he’s mad because he’s defeating the enemies too easily. Frankly, he really wants to be playing FPS games but doesn’t have a computer. I refuse to play with him.
The first player mentioned is the current GM, and while he’s also hit or miss, he’s pretty good when he hits.