1. Massive amounts of mortal combat. Can RPGs grow out of killing things and being a walking engine of destruction already? Adolescence was fun and all, but seriously...
2. Retarded puzzles that solve themselves. Buy every single Myst-clone there is. Buy every single puzzle-fest adventure there is. Study the puzzle design. Now copy it in your dungeon. Now make skill-checks give me clues if i want or need. Is it really THAT hard?
3. Loot, loot, loot. "I genocided an underground society and all i got was this lousy combat bonus." Seriously: I don't care for spell scrolls, i don't care for weapon modifiers, i don't care for armor class, i don't care for chests full of gold coins. Can we mature already? Thank you.
4. Shallow dialogue. Again, a hint: Take all the effort you put in making +5 daggers of chain-reacting supernovas and ridiculous amounts of combat encounters. I don't want to spend half an hour killing orcs. I want to spend half an hour discussing shit with interesting characters and trying to convince them of some random shit, being unsure of which among thirty diferent dialogue options is the one who will not result in my game geting terminally screwed.
5. Social encounters that solve themselves. "Click here to apply Diplomacy and win". No, thank you. Use skill checks to activate new, deep, complex dialogue trees and then leave the player to navigate those new options all by himself, get screwed, and two days laters notice he can't win the game. If i wanted to care only about mathematical probabilities i would be playing Blackjack, not a bloody cRPG.