Since I haven't seen either of these two complaints mentioned I'll throw them out there. Both of these are inspired by current games I've played.
Junk loot. Seriously.... Dear developers, stop it
. Certain titles which shall remain nameless even have junk loot tabs in the inventory screen. You then get to find this trash littered in the game world, pick it up, admire it's uselessness and sell it to the closest hoarding NPC you find. I don't like seeing it, looting it, selling it or engaging with it in any fashion. It adds nothing positive to game play. If existing in-game economies need adjusted then adjust them directly. Please, stop tossing in trash as a secondary form of in-game currency. This falls right in line with the excessive loot commentary earlier in the thread (not sure if this is what those comments meant or not).
Second, marathon quest design. Perhaps this is a poor description but nothing else immediately comes to mind so we will go with it. By this I mean going to area A, talking to a NPC then having to go back to area B on the other side of the universe to perform the next step. Rinse/repeat this procedure four or five times. It's perfectly acceptable to make this type of trip once. It's highly irritating when you have to spend an eternity going back and forth, traversing the entire game world each trip, to have 30 second conversations. Forcing a player to do this isn't fooling anyone.