According to Diablo II, the canon hero who defeated Diablo in Tristram was a Warrior: the wanderer who is possessed by the Lord of Terror is clearly a man, ruling out the Rogue. His skin is pale, implying he is not the dark-skinned Sorcerer, and in the opening cutscene, the wanderer leans on a sword, the weapon most closely associated with the Warrior. (Plus in one of the cinematics Marius says "He told me he was once a great warrior.")
Blood Raven (the corrupted Rogue from the first act of Diablo II) was evidently the Rogue in the first Diablo game. Akara and Charsi say that Blood Raven was a rogue captain at Tristram, battling Diablo. They say she returned unlike before, bringing an evil influence. Shortly thereafter, Andariel's uprising in the west began and Blood Raven began raising the dead.
The Summoner, the corrupted Mage from the Second Act that was impersonating Horazon, was supposedly the Sorcerer in the first Diablo game. Jerhyn and Drognan speak of a near-insane Vizjerei mage who arrived in Lut Gholein (presumably seeking Horazon's sanctuary) claiming to have fought against Diablo in Tristram, suggesting that mage became the Summoner. The Summoner is also dark skinned, like the dark-skinned Sorcerer in the original Diablo.