[MENTION=71699]vonklaude[/MENTION] While the designers may have had something specific in mind for the game as they envision it, and I can't argue that they don't have some kind of expertise in the game design thing (ie they get paid for it and I don't), their approach, at least as spells go, does not mesh with mine. For example, as you are correct in terms of casting potential, I place different value on casting strategy versus damage. For me, the fact that Fireball can hit a lot more enemies from a much farther distance more than makes up for the power difference. That's the reason that Fireball is a 3rd level spell, not the amount of damage it does. Enemies you can hit with Burning Hands are right in your face and can very easily hit you back. Burning Hands is a sawed-off shotgun, while Fireball is Rocket Propelled Grenade. Each is deadly, but the situations in which you are going to use them are very different.
As to what you mention with Tempo, I'm a little confused. My argument is not that Burning Hands cast at a 1st level spell slot should deal as much damage as a Fireball cast using a 3rd level spell slot. In that situation, Burning Hands absolutely should deal much less damage. But if you are casting Burning Hands using a 3rd level spell slot, you are already sacrificing the huge damage potential that a long range, wide affecting fireball can do. Why nerf it further with also making it do less damage?
As for #4, I disagree. I don't see higher level spells being less flexible, unless by flexible you mean you couldn't nerf a higher level spell to deal less damage/have less effect to be able to use a lower level spell slot. For me, as an example I used previously, $5 is $5, whether its quarters, singles, a fiver, or whatever. Just because a $5 bill has less flexibility to be used in coin machines, shouldn't mean it has its value reduced in some way.
But I probably MOST disagree with #5. Players should dictate what they get excited about. If they are more excited about casting their own personal signature spells (ie Burning Hands, Scorching Ray, whatevs) as higher level spell slots, why should we punish them because of it?
As for #6, I've already mentioned that Fireball and other higher level spells differentiate themselves in other ways. Area of effect, number of targets, ability to repeat damage across multiple rounds... that is plenty of variety without impacting damage. For me, damage should scale directly so that all spells of a given level have relatively equal damage. A 9th level Meteor Swarm should be equal to 9th level Fireball should be equal to 9th level Burning Hands. The difference is that Meteor Swarm covers an insane amount of area, Fireball a bit less, and Burning Hands is right in front of you.