I more or less agree. The most immediate path to sharply improving as a team (beyond miracle trades or whatever) is for one of our young guys to start to emerge as a legitimate star-caliber player, within a notch or two of All-Star status.
That's a huge missing element, even more so than rim protection. A guy you can not only count on to make plays, but who draws the defense to himself to open things up for our role players too. Because Rondo really can't be a #1 guy, he needs that star to play off of. Neither can Green, though he sure can look like a star in highlights.
Most likely candidates are Sullinger, Olynyk, and Smart, probably in that order, but the only one I see that looks like he has the mindset to step up like that is Smart. But his game still seems much too limited (and maybe injury-prone) to get there any time soon. It's frustrating, but cause for some optimism, too. We're not a good team, but we're not that far away from being a good team.