The F/A-22 also has an inherent air-to-surface
capability." It can already lug a couple of JDAM's. So how does that even
*require* an optimized ground mapping radar to allow it to strike ground
targets with significant precision?

I'm not a bombardier, but I think the SAR radar is necessary for the INS
inputs. The INS being only updated by the GPS, and only if the GPS
isn't being jammed (which will be unlikely down the road). I think I read
where GPS only doubles the accuracy of the INS (50 feet versus 100 feet).

Without SAR, and GPS being jammed, you'll need a good pair of TACAN's,
which some enemies don't seem to provide :-)