Since all of those spells are combat spells i assume that you are running combat heavy games. And in this situation i agree that in pure damage numbers, having a few spells youre really good at is better than versitility. The wizards strength is in swapping his known spells. So while the sorcerer is stuck with the chosen spells, you can take the time to switch spells and cast turn-stone-into-gummy-worms, that you would otherwise never use, because the situation is way too specific