What I want to see for the sorcerer?
Lots of small thematic spell lists that cover all levels. So there's an "Ice" one that has a bunch of ice-themed spells, and so on. Each of them also comes with a special ability (or maybe more as you level up).
Likely also need to have lots of variations on existing spells, such as you can learn Fireball, Thunderball, etc.
You don't have spells known, they have spell lists known. So you might pick three spell lists like Water, Blood and Storm, or Wind, Cloth, and Portals. You have all the spells on those lists. If there's a spell overlapping on multiple lists (perhaps even Fireball and Iceball from above) there is some bonus to make up for the reduction in choice.
Metamagic start at 0 SP to use, only the best of the costs more.
So you have a thematically limited list of spells, which will restrict you from picking "the best" spells always. It ends up being more separate effects around the same few themes. Within these themes you are the master in a way that wizards can't replicate because not only do you have a wide variety of spells but also you are adding metamagic to every single one of them because you have free options so why not.
Subclasses both come with additional spells specific to the subclass, and with some real features that change playstyles. Not like Wizards where it's a small adjustment to their spells, but something that makes a dragon sorcerer feel like a dragon, and play differently than a wild mage who plays differently than another. Connect these all strongly to bloodlines, so you don't get Storm sorcerers - that's based on spell list choices (which do give some special abilities so could be somewhat duplicated picking the right spell lists known).