Surely that bit of the Venn diagram which shows what the Herc can do which the A400 cannot is pretty small and diminishing (much as I love the Herc, growing up as I did under the shadow of Lyneham)?
As for SF uses, there are plenty of off-the-shelf civvy options which could meet that need (Kodiak, Caravan - hell even the mighty Skyvan!). Why not add this capability to JSFAW as they did with the Dauphin?