The biggest change between the 1978-79 team and the 1979-80 team was the coaching and defense. Dave Cowens was an awful coach, and the situation wasn't made easier by the chaos of constant trades and the collection of cokeheads he was saddled with. The Celtics unloaded Curtis Rowe, Marvin Barnes, and Bob McAdoo (who was fine when he arrived here, but functionally useless after a couple of months with the coke dealing Barnes). In '79 Tiny Archibald was hobbled by injury, averaging a mediocre 11/4 line in part time duty in sixty plus games and Rick Robey didn't join the Celtics until January of '79. The next year they had stabilised the roster, got Archibald back to run the offense (he played 2800+ minutes that year, posting a 14/8 line, as opposed to the 1600+ minutes in '79 ), and added M.L. Carr & Gerald Henderson for depth. Factor in the better coaching and they were set to make a run. And, yes, having a hall of fame point guard uninjured was a big upgrade.