Something that could be done in regards to the Necromancer (Death Mage sounds silly, be real) would be to move Haunted Golem’s trait to an early game Death Creature. As the Haunted Golem summon does indeed count as a summon/temporary creature. Also, maybe having Friden go “Hey, you look kinda glum…”, or something, as a little hint to Necromancers that he has some of the most important spells for the class.
Sorcery, however… umm, well, a good place to start would be to realize that Spell Strike is just bad and that the Gorgon has nothing interesting to offer. Actually, come to think of it, it might be an idea to take a good, long, hard look at the Sorcery spell school and some of the creatures in it.
Admitedly the Wizard class is amazing and my personal favorite. But it really does struggle in the early game with that few Spell Gems, two poor creatures and whatnot.