The AGESA code was always an awkward fit into coreboot. It was more like a badly designed artificial limb than a real part of the code base. I understand the idea of encouraging vendors to commit source but, at this point, the AMD ship has sailed off to Port Binary Blob. AGESA was helpful in its time but I think I'm with tpearson on this point.
I believe we should drop AGESA on any boards that have native support, and the sooner the better.
ron