Some spells actually upscale nicely (long duration, increasing area size spells, multiple targets) while others gain value from the DC increase without touching the level. Both DC and scaling up to a higher spell slot can benefit at the same time.
It's not that there isn't value in upscaling.
Not all spells upscale equally.
Usually higher level spells are more powerful than lower level spells in the same slots, though. Upscaling is usually option "B" for classes that are tighter on spells available to cast. Knowing which spells to cover various goals when a character has fewer options is a system mastery issue.
In the end, not all low level spells are going to be as useful at higher levels. C'est la vie.
The bolded part is definitely an issue. More often than not upscaling just isn't worth the higher level slot IMO.
They have that. Upscale. *ducks
LOL you had better duck!
Seriously, though. Consider a spell like Magic Missile. I get it. If you scaled it without upscaling, you would get 11 missiles maximum or around 50 damage with no attack roll or save, for a level 1 spell. That is pretty powerful, really I think. But would 6 missiles, around 21 damage, be unreasonable at 17th level?
My idea, since cantrips scale with tier, would be to upscale spells one level for each tier.
Tier 1 (1-4) would be first and second level spells.
Tier 2 (5-10) would be third through fifth level spells.
Tier 3 (11-16) would be sixth through eighth level spells.
Each time you reach a new tier, your spells gain one spell level. At maximum 17th-20th levels, it would look like this:
First and second level spells are cast 3 levels higher.
Third through fifth are cast 2 levels higher.
Sixth through eight are cast 1 level higher.
Or you could limit it even more:
1st and 2nd are 3 levels higher
3rd and 4th are 2 levels higher
5th and 6th are 1 level higher
Or whatever. Think of it as free upscaling. When you reach tier 2, your level 1 and 2 spells are one level better. For Magic Missile, you get one more missile for free. When you reach tier 3, you get another, and at tier 4 you get 6.
I don't think this is too powerful really, but it is just something I am throwing out there. It does mean something like a cure wounds cast as 1st level by a 17th level caster would upscale 3 levels, making it 4d8 for free instead of 1d8... Is that
too much? I don't know, I'll have to sleep on it.