Just a little theory I've been thinking about lately.
Both are talented, but ultimately flawed players that need to be surrounded by exactly the right sort of talent in order to flourish. Both are borderline "max"players whose reputations might exceed their actual abilities.
In my opinion, both are the type of players that should NOT be kept by rebuilding teams, as they will only continue to delay the rebuilding process and eat up valuable cap space that can be used to facilitate better deals for the team's long-term health.
I would hate to see my Celtics do what the Knicks did this offseason, which is essentially confine themselves to basketball purgatory for the next half-decade.
Keep in mind that since 08-09, advanced stats measuring Rondo's performance have fairly steadily declined. This is during a time when Rondo should be entering his prime. Keep in mind that the next contract Rondo signs will continue to pay him until he's ripe old 33 (very old, for a point guard that doesn't have a 3 point shot). Even if you consider Rondo to be a max player now, will he still be in 4-5 years, which would be when the Celtics are back in contention (assuming everything goes as planned)? Highly unlikely, based on the stats trend.
One of the reasons that Rondo is so controversial is because a lot of what he does is so hard to measure. But lately the intangibles that he used to thrive on (such as his defense) have been withering up. Expected progress in FT's and 3 point shooting simply never materialized, and at 28 it's pretty silly to assume that they will. Rondo also never drives to the basket anymore, which is partially why his fg% has been dropping like a rock for years at this point.
Long story short: has Rondo played like a max player in the past? Yes. Will he ever regain that form? Maybe. Is it worth it to gamble the entire future of this team on one player defying the odds and playing like a top player again? I would have to say no.
Rondo is our Carmelo. For the love of all that's holy, let's try NOT to be the NY Knicks.