So, pretty basic idea. I'd love to see an XP boost that *isn't* based on time. As for why? Hear me out!
XP boost which are time-based, with it counting down while in quest, are great and all, but they encourage one single style of play - fast and furious. Characters who simply are designed to kill faster and harder, to rush past lore, quest dialogue, traps, etc. *will get more xp.* Simple as that. In a game like DDO that just doesn't seem to be entirely intuitive.
Now, mind you, I'm not saying they should remove timed XP pots, far from it. Leave them as are, by all means. I just think it'd be awesome to add in a type of XP boost/potion which adds a certain amount of XP in a bonus fashion, whatever percentage, as you earn it, regardless of time. That way people who want to play less optimal builds, or to take their time with quests, aren't essentially being punished or losing out on their bonus time for not going at it as fast and hard as possible. Ideally, I'd think it would be great to look at the amount of XP generally earned on an XP pot, average it out, maybe even drop that value a bit, and that'll be that. Maybe roughly adjusted for every so many level ranges or whatever, I dunno.
Just a thought. I hate to have to feel like I must rush sometimes because the little bonus timer just keeps ticking away. And heaven forbid if you get hungry, someone comes to the door, you get a phonecall, etc. while in a dungeon and have to pause.