I had a static friction problem with my Warthog stick, and when I opened her up there was not enough grease on the ball joint. I bought a can of M-kote EM-30L lube off ebay and coated the inner ball and outer ball with this new grease after cleaning off the old stuff. I also put a coat on the rubber ring that sits on top the ball(the one someone has had problems with de-laminating). This rubber ring was previously completely dry. This has really improved the static friction problem for me, the stick is much smoother. You could probably just borrow some stock grease from the spring as well.
One tip, for those of you whose Warthog doesn't center perfectly and or has center play, try rotating the plastic retainer that sits on top of the ball and spring from it's original position when reassembling. My stick had some play in the y axis when I first re-assembled it, and when I took it back apart I rotated the top retainer until the stick now has no play and will center perfectly in the x and y. Not a guaranteed fix, but worth a try.