Tough to say. He was obviously very talented, but lots of talented players turn out to be pro disappointments.
He had good size for a 3, was athletic, long arms, and got up very high on his jump shot. It looked like he was going to be a good player. At the very least, him being a solid rookie could have helped Bird & McHale get some rest. McHale actually ended up breaking a bone in his foot that next year. It was clear in the finals that the Lakers were just better and deeper. Mychal Thompson was a great addition.
I don’t think they draft Reggie Lewis though if they get Bias. They would have already had 2 SFs in Bird & Bias.