His 2006 season was his best because Larry Allen played very well that year after coming over as a FA and Jonas Jennings was actually worth a crap for a majority of the season for the only time in his stint with the Niners. Best OL play he has had in his career. Plus, Smith actually did pretty well that year so they had at least some threat of a passing game to keep the D honest. Plus, they kept games close so they were able to commit to the running game.
The last three years, their line play has sucked and until the 2nd half of 2009, they were usually behind, so they couldn't commit to the run, meaning less opportunity.
Sometimes statistics don't tell the story. When you're behind and your line sucks, hard to run the ball and there is less opportunity. With a solid defense to keep them in games, a better OL and an improved passing game, I expect Gore to get in the 280 carry range and another 55 or so receptions. I even figured in two missed games to keep the "injury prone" argument out of it. With the kind of football Singletary wants to play and the fact that an improved passing game should reduce the 3 and outs, I don't think 20 carries a game in high. I also don't think his career average of 4.8 is too much to expect, so assuming he doesn't miss more than two games, 1400 yards rushing and another 400 yards receiving is reasonable. If he does play in all 16, 2000 total yards in achievable.
One last point. I know Davis and Iupati are rookies, but both are big upgrades over what they had. Also, Sims, Baas (or Rachel), Wragge and Snyder (not a bad guard) give them some depth if they do have an injury. I may be overly optimistic here, but I really think the O-line is going to be good this year.
Anyway, we'll see...............