pfff...personally I don't see a need.
Actually, with the whole new battlesystem I don't see a need for armories at all except that I still need orcs for scouting and for upgrading the workshops.
Besides, of course one can introduce magical buildings for everyting, so next would be (and probably will be) the magical factories. But considering the prices it's mostly something for the buy-to-be-on-top players.