There have been a lot of comments about Hit Dice, but I'm not sure that reducing their hit points would be very helpful for "nerfing" the wizard. The last wizard I played didn't really need hit points past a certain point. It seems like by the time I got to 8th or 9th level, I hardly ever took damage, and even if I did, it was less than 10-15 points.
14. Back to 3 saves (Fort, Refl, Will) like 3ed.
15. Death saving throw now a DC 15 Fortitude save (and Concentration now a Will save).
Oof. This goes far beyond the "nerf the wizard" topic. You're changing all classes now, and all monsters, and the fundamental way that all spells, abilities, traps, conditions, and death/dying work. I think you'd be happier playing 3E D&D. (And that's not intended to be derogatory...3rd Edition is an excellent system! I played it for over a decade before switching to 5E. But I think most people would rather play one or the other--not try to mix the two.)
I agree with your points about scaling cantrips, though. They shouldn't
automatically scale with level. It would be more interesting to give the player a choice, similar to the Fighter's fighting styles.
Like: you know how Fighters get to choose a fighting style at 1st level? "Okay, do I want the Defensive fighting style and get a bonus to AC? or do I want Archery and get that bonus to my bow attacks?" Well, what if the Wizard got a Casting style in similar fashion?
"Hmm, if I go with the Arcane Recovery, I get to recharge a few spell slots. But if I go with Cantrip Mastery, my cantrips scale with level. And Ritual Casting could be nice too...hmm, which one will I choose?"