I wonder if high level D&D were played more if PCs, NPCs, and monsters where just limited to a few things.
I like the idea from Daggerheart where you got cards and as you leveled you replace low level cards with high level cards. And some cards are simple like add your Agility to Armor.
Or like 13th Age where high level casters lose their low level slots. So a 15th level wizard would only have 9th, 8th, and 7th level slots. So if you really wanted to have mage armor at the very high levels you would be casting it as a seventh level spell and using up one of your spells known on a first level spell.
I like the idea from Daggerheart where you got cards and as you leveled you replace low level cards with high level cards. And some cards are simple like add your Agility to Armor.
Or like 13th Age where high level casters lose their low level slots. So a 15th level wizard would only have 9th, 8th, and 7th level slots. So if you really wanted to have mage armor at the very high levels you would be casting it as a seventh level spell and using up one of your spells known on a first level spell.