IMP, the team you listed would not be a tanking team, and would not take the Celtics to the lottery. I would watch that team, too.
I think that team would be better than the worst 4-5 teams in the league, but they wouldn't win a lot of games. You have to take into consideration that Rondo and Sullinger will spend the first few months of the season getting back to where they were pre-injury / surgery.
For me its still a lot more gratifyig watching pierce drop 40 on the cavs or KG continue to do work on guys like blake griffin kevin love etc etc.
I honestly don't get what's exciting about the rebuilding process. At least after like 15 games when you'll be like "holy moly this is the most brutal team" "We'll never won with any of these guys"
I find that in these discussions using the metaphor of television shows / movies is really useful.
So for me, bringing the gang back would be like watching Season 7 of Lost, or making another Star Wars trilogy that is set after the first three movies (oops!).
At some point it's better to just let a good thing lie and be what it has been. I don't really want to watch more of the same thing, especially when it's only sporadically as good as it used to be and is frequently painful.
Whereas a new, exciting show with an unproven cast that has the potential to come together to make something special holds more intrigue and episode to episode excitement for me, even if it won't necessarily reach the same heights as what came before.
Still, there's a good chance that what we get next with the Celtics will be about as satisfying as "The Event" or "Flash Forward" were as replacements for Lost. But we won't get the next Battlestar Galactica until we take that plunge!