There's no way to know what he could've been but I do feel very confident in saying this: If Bias had survived, the Celtics win the championship in '87. That kills me.
I think this is pretty wild: I remember where I was when I found out Len Bias died of an overdose. Probably there are lots of older guys that can say that but I was born in '88. I still remember exactly where I was when I found out:
I was 14, the summer of 2002. After the Celtics made the ECFinals, I bought a Boston Celtics Encyclopedia. A history of the team. I was in the back seat of my parents car, headed to my grandmother's house, when I got to 1986 and the championship and then the part about Bias. I was shocked that something like that could've happened.