First off --
Let me say that I really enjoy the new quests. They're different, fun and the puzzles are very challenging.
That being said, two months from now no one is going to run them. Why? Because the return on your investment is not worth it. I'm not saying every quests needs to dispense XP on tap, but I do think if there was a more balanced ratio of XP to time across all quests then people who use more of the content then they currently do.
The whole thrust of the First-Time bonus is to get people to do more than just farm one or two quests by rewarding them for running different content. However when you have a quest that takes 15 minutes and gives you 921 base xp, or a quest that takes you 3 minutes and gives you 1k base xp most people are just going to run the faster quest.
I do not think it would be out of line to double the base XP for all the new quests. The only exception would be Ghost of a Chance where I would keep the base XP the same but double the XP for solving the big puzzle.
I think this fix could be applied to the game as a whole. There is a good deal of content out there, but lots of it never gets touched because the return on your time / risk / etc is not worth the investment.
Well, thanks for listening.