So starting off will say I don't play either of these classes much but have played around them so I have no idea if this will fix them enough or not but figured I'd throw it out there. And this is assuming nothing else changes and it's just these changes.
Give Wizard/Sorcerer clostiered clerics refund chances on top of arcane flux. For generalist/sorcerer just the normal amounts for specialist wizards make them have double the refund chance for their specialization and like half the refund chance for other schools. Obviously for problematic spells that shouldn't be as easy to get back give them a lower refund chance like how elementalist/Hemo have a higher cost to use them.
Give sorcerer bloodlines that make them have better refund chances on specific spells that fit the theme of the bloodline as well as some ability they can add to their kit from those bloodlines.
Give them access to powerful spells that can help them out and only those two classes have. Their supposed to be the masters of magic either by studying it all their life or by having it naturally due to blood.
More of a in general spells things make spells do something even on a successful save by someone. If a spell dazes for a round on a failed save make it daze for a second or so. Just so a spell isn't entirely wasted just because people and such have high saves.