In the late 80's, the Celtics could have traded Larry Bird to the Indiana Pacers for Chuck Person, Herb Williams, and Steve Stipanovich, and Kevin McHale to the Dallas Mavericks for Detlef Schrempf and Sam Perkins.
Bias and Lewis had lived as well, this could have been the team in the early 90's:
Brian Shaw / Dee Brown
Reggie Lewis / Danny Ainge
Len Bias / Chuck Person / Rick Fox
Dino Radja / Detlef Schrempf / Sam Perkins
Robert Parish (aging) / Herb Williams / Steve Stipanovich
A LOT of forwards, but great depth and versatility. They could have competed throughout the 90's.