Meridian: Vaykor Kittag would be totally awesome, but it has enough love already. Maybe a Vaykor Halikar
Hexis: Telos Boltace is the obvious pick.
Suda: Synoid Gram - A more elegant weapon for a more civilized age. xD
Perrin: Secura Serro - practical in peace-time too.
Veil: Rakta DHS, maybe Sylva for righteous flames.
Loka: Sancti Reaper (chopping trees with it is strictly prohibited)
Meridian: would be obviously Grineer weaponary. I'd prefer Jet Kitty or an Atterax
But Vaykor Cleavers would be a cheap cop out (not like we've seen it happen before V.Hek)
Suda: Lecta, Amphis could be fun, but I hope DE brings back fistycuffs back like the Obex or Kogake
Loka: A variation of Nikana or even a Dakra