There's a lot of people in this thread who seem to keep making the mistake of assuming combat is the only balance metric.
Maybe a fighter could win in a straight-up fight with a wizard. This wouldn't be anything particularly new to 5e. Pathfinder, 2e, and 1e wizards also loose in a straight up fight with a fighter (ability to take damage and disrupt spells FTW). About the only way a wizard wins in that scenario is by using some sort of Save-Or-Die effect and getting lucky on the dice (or twinking their spell DC). If they win initiative, and the fighter fails the save, then maybe they come out ahead. If not, they're toast.
The way a wizard beats a fighter isn't in combat. It's in doing things like avoiding combat to begin with (things like Charm or Teleport aren't there to win battles, they're there to prevent them). In a lot of ways, if a wizard gets into a normal fight alone, they've already failed.
That's possible to balance because combat isn't the only measure of character power. I'm not sure how 5e is gonna do it, but a wizard in my mind is "spike potential." That is, a few limited times per day, the wizard is CRAZY effective. The wizard is your panic button. They are your nova. They are your big boom effect that might save the day. Their spells are going to save your bacon. But they can only do it a few times each day, and then they're spent. Maybe Fireball does end an encounter quickly. But the next encounter won't go so quickly. The wizard has used their big boom effect, and there's nothing left of that power.
Fighters in this mode are MasterCard: useful everywhere. Wizards might be more like your specific store credit card: more useful than MasterCard, but only under limited, rare circumstances.
That's not the only way you can do it, that's just the way that matches my expectation of D&D magic the best.
