The big issue is that wizards are just a huge pile of mush because of the shared spell list. The necromancer, the conjurer, and the illusionist all show up to the table with Sleep. The abjurer, the evoker, and the oracle all show up with fireball. There's almost zero differentiation between spellcasters that should have different abilities and feel.
When 5e first came out I tried to play a necromancer. I wound up with the exact same spell list as the other wizard at the table and effectively the same abilities. Super lame. Things like the necromancer and summoner are just obvious examples of how things could be done differently from 5e because we've seen them handled differently in a million other video games, anime, etc. DnD just needs to step up and make things special instead of relying on the generic spell list as a class feature.