jsac-you know, I have similar thoughts. While I ride a mountain bike a great deal, when I bought the KLX it had been 20 years since I rode a mc in the dirt. The stock tires look like they ought to be great in the dirt, so I thought it was just me not knowing how to ride well! they really do feel like on marbles when on a gravel road.
Know anyone that's tried Pirelli MT21's? they get great reviews, and I know guys love 'em as dirt tires. Anybody tried them on a klx?
doc

 

Here is my $0.02 worth; I switched to Dunlop 606 front and rear after about 1350 miles on the stock 603. The 606 seems to be a much more dirt friendly tire and I just completed my first Dual Sport event in the PNW about two weeks ago. The 606 were very confidence inspiring on the hard packed clay and occasional mud I ride on plus there is a marked improvement on gravel roads. I am not sure they will last much longer than stock tires, however, and would give them a rating of maybe 7 – 8 of 10 for road worthy tires.
The 606 are also a little high priced compared to the other tires.
I think you really have to assess your riding conditions to choose the correct tires.
I may put Kenda 270 on as my next set just to compare, should be in about 700 – 1000 more miles.

Regards