First, your second bullet point is not correct, because its not like KG and Pierce were not at the tail end of their careers last year.
In fact, even though they had Rondo, more than half the team was either not available or playing injured, which is not true this season.
Sure Rondo is out for this year, but we have Jeff Green, Wilcox, Terry, Lee, Bradley etc. this year. Compare that to the quality of support we had last year and you instantly see how much better we are this year.
There is no way Rondo's production equals to that of Jeff Green, Chris Wilcox, Jason Terry, Courtney Lee, Avery Bradley and others COMBINED. Not only the production, we have more bodies this year as opposed to last year.
Next, Brandon Bass does not need to focus less on scoring. Its obvious by now that we have trouble scoring sometimes and you want the most consistent player on the team to stop scoring?
As for the new guys, its upon Doc if he decides to let them play legit minutes instead of last 1 minute of a blowout game.
Lastly, Jeff Green's big plays this season have shown that he is not afraid of the spot light. And if he really is not afraid of them, then "bright lights of the playoffs" should not limit him. As for the end of close contests, I still would like to go with Pierce unless we can successfully draw a play that uses Pierce as a decoy and leaves Green wide open for a shot, similar to the game against Pacers.