At the end of the first Big 3 era, it became apparent that they could not all play together because they were simply too old. I think the new Big 3 era is clearly there now too. Our starting lineup with the Big 3 and JO is simply to old, slow, and creaky. Just not enough athleticism to match up with other teams or to play at Rondo's speed.
KG and JO should never play together. Only one should be on the court at a time, with JO backing up KG. The other big spot should be filled with younger, more athletic players: start Bass backed up by Wilcox/Steimsma. Ray is playing great but Pierce's injury and conditioning are slowing him down right now. Move him to the bench in a Ginobli role and start Pietrus instead. Find situational playing time for Moore (for offense) and Bradley (for defense), as both can run with Rondo.
Replacing JO and Pierce with Bass and Pietrus injects some energy and athleticism into the starting lineup alongside Rondo. Pierce can provide the scoring for the second unit with the younger players, and close out games with the starters. (Hopefully, Pierce will play himself into shape over the course of the season).