I'd take Franklin. Every club has a "gun midfielder" or two (well, maybe not every club, but most of them) but "gun key forwards" are in much shorter supply.
I guess I reckon that unless the player in question is a midfielder of the most elite standard (talking Judd/Kerr/West/Goodes kind of players, Deledio clearly isn't at this standard) then generally speaking a gun KPP outvalues a gun midfielder.