That depends on how unbalanced it is, and how much people like it how it is.
Personally, I’d love to have fireball do even more damage but be harder to use safely. Really I want magic to interact with the world more in general. Whether that’s written into spell descriptions or general rules for Spellcasting and DM guidance on running the game, I want an ice AoE to create a patch of frozen ground, a wall of fire to radiate heat above it and catch things on fire within 10ft of it if they’re flammable and dry, and fireballs to fill the space they’re in.
But since that won’t happen, I’m fine with fireball doing a couple dice less damage, I guess. (Or whatever spell being lightly “nerfed”)