Creating an incentive for covering more ground between Extended Rests seems like a fair carrot method to encouraging players to do more in a day. I mean, when death is eminent you're going to pull out all the stops to survive. If you're going down you better go down swinging with everything you've got.
The problem is Nova-Rest-Nova (when you can do it) gives you all the rewards with the minimum risk. If you got a bonus multiplier for your XP for tackling more challenge between extended rests (say 10% per standard XP budget unit) then there would be a compelling reason (other than the DM hammer) to accept a nominal increase in risk.
When you're in a situation where you want to hit more than one encounter in a day as a Vancian caster you're going to sit on at least some of your spells so you can last longer and only go nova as a last resort.
- Marty Lund
The problem is Nova-Rest-Nova (when you can do it) gives you all the rewards with the minimum risk. If you got a bonus multiplier for your XP for tackling more challenge between extended rests (say 10% per standard XP budget unit) then there would be a compelling reason (other than the DM hammer) to accept a nominal increase in risk.
When you're in a situation where you want to hit more than one encounter in a day as a Vancian caster you're going to sit on at least some of your spells so you can last longer and only go nova as a last resort.
- Marty Lund