About 50% of the reason he was reworked was due to his hook, and the other 50% was because he made lots of other heroes obsolete. His kit was never balanced due to his hook. I’ll get to the hook “balance” issues later. But I think most of the reason they reworked him was because his hook was broken for the longest time. I don’t mean broken as in OP (although a few versions certainly were that). I mean broken as in, it literally didn’t do what it was suppose to do. I use to hate playing Roadhog until he got reworked because even after 3 iterations, his hook was still super inconsistent. We had one version that pulled people through time, walls, and space, but missed sometimes for no reason; we had one version that pulled different heroes different distances from RH, meaning that he couldn’t always one certain heroes; etc. That’s not counting the minor iterations we got.
Then there was the balance issue. At the time, the snipers were awful to mediocre, and Reaper was rarely used. RH being able to one shot stuff was fine. Him being able to one shot stuff while sitting behind a shield (unlike Reaper or DF who had to get in there with lots of risk to do damage), having healing on a relatively low cooldown (unlike most other one shot heroes), and RH being immune to divers due to his large hitpool and healing (unlike snipers) wasn’t fine. His kit made Reaper, Widow, and Hanzo obsolete because he could one shot people with less skill and risk. Why play Widow to one shot something when Hog could do it with less risk?