In the current 4th edition AD&D rules I think it's addressed the worst. I can't even find a reference to allowing characters to dual-wield unless they have a feat for it, and even then the feat only gives the character a +1 to damage if they happen to have a weapon in each hand.
The 3rd edition rules are the longest, with a table of modifiers and descriptive explanations, along feats that adjust how characters wield two weapons at once. Essentially, anyone wielding two weapons suffers a -6 penalty to their main weapon and a -10 penalty to their off-hand weapon, unless they have a feat which lowers the base penalties to -4 each.
I was actually really surprised that the 1st and 2nd edition rules for this are identical. They're phrased differently, but the initial penalties and ability modifiers are the same. The primary weapon suffers a -2 penalty and the off-hand weapon suffers a -4 penalty. A very high, or very low, Dexterity modifiers will offset or increase the penalty. I'll quote word-for-word from the 1st edition rulebook:
"If the user’s dexterity is above 15, there is a downward adjustment in the weapon penalties as shown, although this never gives a positive (bonus) rating to such attacks, so that at 16 dexterity the secondary/primary penalty is -3/-1, at 17 -2/0, and at 18 -l/O."
Keep in mind, 1st and 2nd edition were written in a time when feats hadn't been imagined yet. I never knew the 1st edition rules were written like that, basically because I've owned a copy of the rules forever but never actually played with them, nor read the rules from cover to cover. This has spurred my interest to see if there are other things that are wildly different from the origins of the game. But mainly I thought I would share this weird little transition over the years.
People often complain about powers getting nerfed in revisionary changes, but nobody ever points out how the rules sometimes get harder, or disappear completely.