Rondo has always been a weak offensive player. To expect him to suddenly improve now that he's past his prime is ridiculous.
He's a really good player, but he needed a certain system and team to be successful. He needs lots of shooters. KG and Bass were consistent mid-range shooters. Ray was the best 3-point shooter alive. Pierce was one of the most versatile offensive weapons in the league. Those guys spread the floor and kept defenses honest. It allowed Rondo to penetrate inside and have the option to kick it out to an open shooter.
I've yet to see any reason to believe Rondo can be successful in a "share the ball" free-flowing offense. He's somewhat of a liability shooting the ball. Defenders will never take him seriously. It puts added pressure on his teammates to score. This team doesn't have the scorers. I don't know how Rondo will get his assists when his teammates don't hit their shots. This goes back to those debates a couple years ago... John Wall vs Rondo. The argument was that Wall would get as many assists as Rondo if he wasn't surrounded with offensively inept players. The argument was that Wall had as many assist-qualifying passes as Rondo, his team just didn't convert the shots.
I've always been curious to see what Rondo would do without his hall-of-fame teammates and a coach tailoring an offense to his strengths and weaknesses. I always thought there was potential for Rondo to be exposed a little. So far, he looks like crap, but there's a lot of factors playing into it. Gotta give him some time to get back into the swing of things. If we have patience, I still think he can be a 12/8/5 guy
27yrs old and Rondo is already past his prime? Wow, that's news to me. I guess Chris Paul, Al Jefferson, LeMarcus Aldrige, and Lebron James are all past their primes too then? The kid Is still in his prime, and should remain in his prime until he is at least 30, just like most other superstars.
And yeah, why would Rondo be successful in a freeflow share the ball offense? His transition game sucks, and he just hates sharing the ball too.

As for defenders not taking him seriously....that's fine with me. He can just continue knocking down mid-range jumpers in their face at a high percentage, just like he did the past two seasons.
I agree that it will be interesting to see how Rondo plays without his fav hall-of-famers around him, but I think he will prove all the doubters wrong as soon as he gets himself back to full health and into a groove.
But who says he no longer has a coach tailoring an offense to his strengths and weaknesses? If anything, Stevens is going to do Just that. Doc used to overly obsess over controlling the play-calling sometimes. Stevens has already stated numerous times that Rondo is smart enough to see things and audible on the fly, so he will give him plenty of freedom to make reads.