Ancalagon
Dusty Dragon
I was with you until you said this. I agree that moving away from Vancian was brave (and good riddance!), but a level 5 wizard only has 9 slots. If he started with a 16 Int, and used his 4th level ASI on Int, he can prepare exactly as many spells as he has slots, so he's as versatile as he could ever be under the paleovancian system. Same with 9th level (the only wizard level after 5th where he gains more than one slot, potentially outstripping the prep slots gained from leveling). If he spent his 8th level ASI on Int, he can prepare exactly as many spells as he has spell slots.
So unless your wizard suffers from a low Int for some reason, he's never lacking a spell prepared that he wouldn't also be lacking if he had to do paleovancian preparation.
hmmm.... say I'm a level 6 wizard, and I have 3 3rd level slots. I memorize (for my 3rd level spells) fly, fireball, and dispell magic.
Under the old system, if we were being swarmed by hordes of goblins, I only have one fireball. But under the current system, I can cast fireball once, twice or trice (or not at all). That is much more flexible no? Perhaps I didn't understand you.