Quote Originally Posted by patchyman View Post
I’ve never played a level 10+ game so I haven’t yet seen this problem firsthand.

That being said, I’ve been toying with a novel approach to fixing it. Basically, the spell progression follows the normal curve until level 6 (10 spell slots total). After level 6, spells casters don’t get more slots, their slots simply
get more powerful (i.e. they gain a new slot, but lose their lowest level existing slot).

A 7th level wizard has 1 4th level, 3 3rd level, 3 2nd level and 3 1st level slots. A 12th level wizard has 1 6th level, 2 5th level, 3 4th level, 3 3rd level and 2 2nd level slots. You can always cast a spell using a higher level slot, so your Shield spell remains somewhat useful.

You have to be careful with your spells because even at high levels you can run out.
This reminds me of 13th Age, which is a good thing - it's a pretty elegant way to cap out how much power you can bring to bear. It might be messy when it comes to certain class features - Arcane Recovery comes to mind immediately, but I'm pretty sure there are others.