To be frank, McHale should have been able to have a higher points average than Bird.
Unlike Bird, who was practically Mr Triple-Double, McHale was low post scoring machine and should have routinely gotten 35-60 pts in many games and series and Bird, 18-22 pts only with his assists (weighted more towards McHale in the post), from 7 to 10.
So McHale should have been 30 ppg, 9 rpg, 2 apg, while Bird: 18 ppg, 12 rpg, 10 apg.