The Smurfiest Wizard Ever!
Sure, but without the right spells protecting you, that 11 HD large ancient red dragon has a 88 point breath weapon--even half of which at 44 kills your magic-user unless he has a CON of 15 or higher. And without that CON HP bonus, a 20th level magic-user would only average 37 HP.Heck the average damage of red dragon's claw/claw/bite attack is 25 hit points of damage.
Oh, and dragons weren't considered nearly as powerful (and were more common) than in later editions. Even in 2E, dragon damage jumped a lot due to their combat modifier IIRC.