I'll try to give my most optimistic view on this:
Pre-injury, I felt like Rondo was a consistent jumper away from superstardom. It would have catapulted him from third best PG to 1(A (behind Chris Paul), and put in in the top 10 players in the league conversation (pre-injury I had him top 15). So, let's say Rondo comes back relatively the same in terms of athleticism (possible, considering how much we've advanced with rehab, surgery, etc), AND Rondo has developed a jump shot out to the three point line. That's a guy who could be your franchise player.
I still don't really have a good read on Bradley, if only because he's never really had a chance to play a FULL season with Rondo. He had that stretch in 11/12 where he was absolutely spectacular, but then last year after Rondo went down (especially in the playoffs), he struggled mightily with the PG duties. I'd like to see what he and Rondo can do with a full season of playing together, as I think they could be pretty disruptive defensively. Hopefully, Bradley works on his spot-up shooting and finishing around the basket this offseason (because he doesn't have to deal with an injury for once) and has a good training camp.
Green is really intriguing. He's a guy who can explode for 40 one night, and then drop 9 the next. For him, I think it's all about confidence, consistency, and creativity this summer. If he can develop that mentality of "Hey, I'm looking like I need to be the min scorer for this team, I need to take every game seriously" then I like him as our starting SF. If he's confident and gets in his rhythm, he's an electric scorer. As long as he consistently puts in the effort, he can drive, shoot, post, etc. Also, I'd like to see him get some new moves this year (especially moves GOING TO HIS LEFT). That would really open up his game. And his defense really impressed me this year, especially the shot-blocking.
I'm a big Sully fan. Love the hustle, banging, post-presence, everything. If he could get some more touches in the post, I'd love to see how our offense would develop. Looking back at his college game, the guy just bullied people ion the block, so I could see him just scoring right at the rim. His passing is also very good for a big dude, so if teams double, he could kick it out, and get the ball swinging around the perimeter until a shot opens up. His defense wasn't that great last year, but he also played less than half a season, so I expect him to improve. He has the potential to be a starter if he improves the defense.
Here's my initial reaction (and ultimately my actual view) on that core:
No shooting, not big enough, scrappy and scrambling on defense, 30-52.