A "minethrower" is the same thing as a mortar, just a more archaic name for it. The Brixia was very fast firing, but very weak for a mortar.
Anyways, the main prob with getting the greeks ingame is that they would need full character models, statics, planes (gladiator), hand weapons, voices, etc; as well as the italians needing tankettes, falco biplane, etc. Remember, the italan army has never been a finished army ingame, and prob won't be for a long time.
So basically you'd be creating 2 full armies for what, 1 map, 2 maps? And oh yeah, the maps take a year to develop.
Sorry, but the devs aren't gonna be getting to the greek army for a long time, if ever. Just the nature of the beast.