For the record, I don't think that your criticism of Rondo is unfair at all. If Rondo could shoot like Chris Paul he'd probably be in the conversation for the best pg (aside from Magic) of all time. I'm also not disagreeing that teams would play him at least a little tighter if he was a better shooter, or that the team wouldn't benefit from his defender playing a little closer to him.
What I'm saying is that he's so good at what he does that he's still able to be an effective offensive player in spite of that. It's true that teams don't worry as much about his scoring as they do about (for instance) Parker's scoring, but it's also true that he's still able manufacture very efficient scoring chances no matter how the defense tries to play him.
In your extended post, I think you were trying awfully hard to conjure up stats to contradict my points which are seemingly obvious. I must say that I am mostly unconvinced but I appreciate the thoughtful response in the spirit of debate. But then you come around in the last two paragraphs, which I quoted above to say you agree with me at least to some extent. Sounds like we may not be that far apart after all.
The only point for point I will continue is the idea of team assists vs. Rondo piling up assists. Point one is yes, I do think that if a team got 25 assists with no single player getting more than say 8 it is better than getting 25 assists with one guy getting say 12 or 15. It would be the same for scoring. The more balanced the scoring, the better in the long run. Harder to defend, less likely for droughts, etc. But that is the minor point not the main point.
The main thing that's missing from your point is the most important, efficiency. If a pass from Lee or Terry was as likely to end up in a good shot for a teammate as a pass from Rondo you'd have a point. I think you'd have a hard time convincing most of the people who watch the team play that this was the case.
I could probably dig up the link, but a year or two ago some Wizards fans, about 3 months into the season, went on to the synergy website and compared all of the passes Rondo made to his teammates that resulted in a scoring opportunity and every pass that Wall made that resulted in a scoring opportunity. They found that the Wizard's scoring efficiency was about 8% higher off of passes from Wall than normal (which, according to an article from 82games, was close to average). They also found that the Celt's scoring efficiency jumped by almost 20% when the opportunity came from a pass from Rondo.
Unless you're arguing that the passes from the other Celts result in scoring chances as good as the ones Rondo gets us, your "spread the assists" idea will clearly make the Celts a less efficient offensive team. Case in point, the Knicks series, where we made plenty of passes but they just didn't result in much scoring.
The main point is that if you take a team (without Rondo) that is getting 25 assists a night, the assist total should not go down when you add a freakishly talented passer to the team. Just like if you added a freakishly talented scorer to a team, you would think overall they would score better (or more easily), not worse (albeit slightly in the case of the assists). This is why Rondo is a bit of an enigma.
Here are our assists (per 48min) with and without Rondo over the last 3 years (from nba.com).
10-11: with Rondo, 25.7 without Rondo, 19.1
11-12: with Rondo, 25.3 without Rondo, 20.5
12-13: with Rondo, 23.5 without Rondo, 21.5
And here are the playoff numbers:
10-11: with Rondo, 22.5 without Rondo, 14.1
11-12: with Rondo, 20.4 without Rondo, 15.1
12-13 playoffs, all without Rondo, 16.8
Again, the team got a short-lived bump in assists after Rondo went out that didn't last the entire season. The team was averaging more assists a game when Rondo went out than when the season ended.
Teams can relatively easily adjust their defense and prevent Rondo from creating the impact he would otherwise be able to create.
If this were at all true then Rondo would be nowhere near the league leaders in assists. He'd be especially ineffective in the playoffs, when defenses are focused and coaches game-plan and make adjustments as the series progresses.
Over the last few years 1) we've heard the coaches of some of the best defenses in the league talk about how important it is to keep Rondo in check, 2) we've seen them fail to do so, and 3) we've got your comment that "Teams can relatively easily adjust their defense and prevent Rondo from creating the impact he would otherwise be able to create". One of those three things doesn't belong with the other two.
In the 2012 playoffs we faced 3 of the top 7 defenses in the league and Rondo scored or assisted more points than anyone in the league except for LeBron in that postseason. How on earth could that possibly happen if it's relatively easy to adjust a defense to limit Rondo's effectiveness?