Majoru Oakheart
Adventurer
As one who from his start in OD&D has favored the magic-user (although clerics rock in their own way, especially in 1E), I have little patience for claims that they are "too weak" in old D&D -- except by comparison with elves in Moldvay/Mentzer Basic (which are simply too strong).
Low level magic users had interchangeably moments of absolute power and absolute weakness.
You'd be attacked by 20 goblins and an ogre and your allies would be yelling, "Run! Run!" and you'd confidently roll up your sleeve and put them all to sleep. They'd all cheer because there's no way they could have defeated all of those enemies.
Then the Ogre who was hiding behind the rock out of the area of effect would come out of hiding and smack you...once...with a club and you'd die. And roll up a new character.
The same thing tended to happen if you fought more than one group of enemies a day.