There are other ways to go about Necro than just Wiz,
but Wiz is certainly fine as is. Most Wiz builds can go
+Int at 4 , +Int at 8 , Resilient Con at 12 , ~Alert at 16
and be perfectly fine and playable the whole time.
Toll The Bell is the newest necro cantrip, and it works.
Get a familiar, Shocking Grasp, Frostburn, Sleep, Shield.
Animate Dead is the skeleton army spell, which needs
a confab with your DM about how small to gonzo
you / y'all want to go with it.