I assume the softness is in the negative, not just the scan. FP4 and Rodinal should be a good combination.
A couple of things come to mind in terms of how you took the pictures and processing procedures. mirror lock, cable release? also f16 is not a particularly sharp fstop for medium format. f8 might be considerably better in terms of resolution loss due to diffraction.
Quality of the light may come into it as well. flat lighting and plus development won't give the same apparent sharpness as more contrasty lighting.
Finally, development. I process in jobo, with continous agitation. Rodinal never gave me the accutance improvements I expected. Rodinal's sharpness is improved with a higher dilution (1:100) and more minimal agitation.
Pyrocat HD and PMK gave me more apparent sharpness than Rodinal 1:50 in my jobo.
edit: just saw the exposure time is 1/30. mirror shake could be a problem (usually worse between 1/4 and 1/30 sec.) BTW, you did use a tripod? at that shutter speed, it's the only way to get a sharp neg.