I would have to disagree that nothing can be gained with a firmware upgrade..especially if the AF algorithms have been tweaked which would be a great gain to me as a BIF shooter.
maybe its the lens firmware?My D300 autofocus is not that great with the 60mm Micro. However, the same lens on the D70, D80 and D200 works just great. Other lenses work very well on the D300. I think there is nothing hardware wrong with the camera or the lens. It has to be software driven.
I have seen other people posting reports about the same issue with the 60mm. I think the new 105mm micro has some issues similar to those of the 60mm. Perhaps it is just my camera but I have friends experiencing the same issue.
A new firmware would certainly help..... I don't think the boys at Nikon will let us have a better D300, they are counting on those D300s sales.