Floater discs can be reground with a surface grinder.
Most shops don't do this since they are expensive pieces of equipment and the cost to operate them is nearly as much as a new floater disc.
I wouldn't say that thin floater discs are junk - just be sure that they are flat! They don't tend to wear as much as cup/warp with use. Aside from the air gap difference, I don't see a big difference between say a .060" and a.085 floater as long as they are set up correctly.
My personal opinion is that all of our clutches would benefit from thicker discs (floater, backing plate, friction discs included.)