You are remembering incorrectly. Pre 1.03 was a borderline disaster, especially with regards to skill balancing.
Still amazing, but 1.03 and especially 1.04, and then 1.08 post expansion were clear improvements in a ton of critical ways.
The expansion introduced spell delay, which completely destroyed all fun I had ever had with the game. Waiting a goddamn 2 seconds to cast another spell was bullshit, and I don't care whose computer couldn't handle it before. 1.03 just nerfed Corpse Explosion, which was dumb, but it didn't change the game significantly. Corpse Explosion stayed great. I just looked at 1.04's patch notes, and I see no balance changes, just bug fixes (which are obviously always a good thing).
This is a classic, though:
Duriel's graphics are pre-loaded before entering his lair. This minimizes the chance of getting killed by him before loading is complete.
My computer was so bad that the first time I killed Duriel was when I played a Thorns Paladin. I just mashed potions while he beat me up. He died before my screen loaded...
Also, I remember MS LE nightmares. I only played Hardcore Mode, you see. An MS LE unique was basically when you log out. The only times I would risk fighting them was when I was playing with someone that wasn't careful enough and the MS LE killed them, so I had to kill it to retrieve their corpse so they could start a new character with some gear.