I've heavily gotten into questing since I started playing again, I love how they're setup and how they progress, but there are so many that have been bugged, I think this idea might really come in handy.
Alright, somewhere in the quest description, we need something I'm calling the "step-ladder". This would be a list of how many steps you've completed in a quest, above the list being the quest's name. Say you're on step 2, and it bugs on that part...if you click back on step 1, you can go back and redo that step in the quest, the items you gave to the NPC before the quest bugging being restored back to your invintory upon doing so. If it bugs on step 1, you can click the quest's name and it will "reset" the quest, making it possible to either read missed text, or simply give it a nudge so it'll take the correct answer you've been trying to give it. I think this would end a lot of problems people have been having with quests (I know it definately would me), and speed up the testing process for quests by a pretty fair amount.