(wry look)
Remember the 1E monk? Remember how difficult he was to play? (Remember how many players said he was useless?)
The low level wizard was worse, as we know. Fire your magic missile, hide the rest of the day (and hope you get enough sleep the next night to actually memorize something.)
Sleep was a neat spell, commonly memorized. Burning oil worked for the wizard as a 1st Level Character Ultimate Weapon, just as it did for others.
But still, how can she (the young lady who is a human wizard) compete against that elven girl, who is a wizard and also a fighter?
The elven girl, fighter/magic-user, has AC 7 until she casts her spells, then dons her armor and is AC 2. She has 12 hit points. She wields a sword in either hand (back then, it was easier to do that, especially with high dexterity.)
Sorry, but the bladesinger (or precursor, in this case) wins every time.
And so, when she reaches levels 14/14, she casts Nymph's Aura, and everyone looking at her (no distance limit, see FOR5 Elves of Evermeet) saves or dies (nice way to take out half the Morgul Host on round 1 ...)
And she has the powers of a 14th level fighter as well.
Humans, eat your hearts out. Or, rather, give your hearts in loyalty to the elves, because they are your new rulers (look on the bright side, it could be worse: the illithid could be your new rulers. Aren't you glad there are elves around to protect weakling humans?

)
So, when all the complaining about broken wizards reached my ears, I remembered all those fighter/mages, and how they took off the level limits, and multiclass characters advanced almost as fast as single class characters, and ... well, you have a Gaggle of Frolicking Elves with Attitude Problems Towards Humans And Game Balance.
(If you think Nymph's Aura, 7th level, described above, is a broken spell, that's nothing. I can show you some truly *broken* spells. If only you knew. Even the 1E Shapechange can't compare with what I could show you.)