I know I am a minority but here is my viewpoint
EXP is by definition "Experience points" not "Reward Points" it is a representation of the overall development of skills and abilities of your character.
The reason why you get quest experience is to represent the experience one gets for doing a series of tasks that doesn't really fit in with combat or that is the result of multiple combats.
of COURSE you should get more experience for "doing it the hard way" and slaughtering everyone versus the easy way of simply picking a lock in the back and waltzing in...
Of COURSE talking someone down shouldn't give more experience then fighting the dragon they were going to release otherwise.
