In my opinion, the wizard is an excellent character class as-written. I really enjoyed my Human Wizard (School of Abjuration, Sailor background) that I played in our last campaign...I played him for just over 2 years, rising from 1st level all the way to 16th level. My character's role in the group was the "spell-breaker," responsible for removing curses, dispelling area effects, debuffing enemies, breaking charms, and countering incoming spells before they could detonate, that sort of thing. It was a high-magic campaign so this really kept me on my toes! Even against non-magical foes I wasn't bored: my character was sweeping the board with Lightning Bolts, targeting BBEGs with upcast Magic Missiles (or Banishing them outright), casting Haste on our Fighter, and confounding our enemies with Misty Step, Blur, Darkness, and the like. The great part of my Wizard was that he made everyone else in the party that much greater.
If I had one gripe about the Wizard, it would be the spellbook. Having to create and manage both a list of spells known and a list of spells prepared felt like a lot of work to me. But that's a very minor gripe...it wouldn't keep me from playing another wizard in the future.
Four stars, would recommend.
