If the Wizard class in 3E was specifically designed to only facilitate the Controller role (or any other, specific role), it would have worked. But it wasn't.
The Wizard could, say, summon a Monster to get his very own Defender. No Fighter needed to fulfill that role. The Rogue may be able to sneak attack for 1/2 level d6, but the Wizard could use Fireball to deal 1d6 per level to multiple targets. Sure, that's a lot of control (20 ft radius burst FTW), but it's also a boatload of damage.
The only role the Wizard could not fulfill was that of what 4E calls the Leader. (But the "only" component it couldn't fill was the healing, the buffing it could get nailed down - which, to be fair, was at least also fun for the rest of the party, since it made them better at what they could do.)