I think its great that you have more freedom now to maneuver, I'd like to add a thought for your consideration:
If you are adjusting XP based on completion times, I do hope you won't overly favor those builds and playstyles that can run the quests the fastest. In fact I'd go so far as to suggest considering a small additional XP bonus if the quest takes a long time, so we are encouraged to play more diverse builds (and so those of us who are flower sniffers and/or slow on the keyboard and/or chose builds that have a low kill/min ratio are not overly penalized.)
In fact, some quests may not even be completed often by alternative builds and may not even be included in your data - I realize there's no way to quantify that, I'm just throwing these thoughts out for consideration in the decision making so DDO can maintain the widest possible appeal to tbe broadest possible player base.
speaking only for myself, I cringe everytime I read about kills/min and xp/min. To me this is an RPG, not a racing game.