I would like to see Yuuzhan Vong Empire.
Or maybe Black Sun/Hutt empire. Think there would be quiet a few number of classes in criminal organization of black sun. Crime lord as dps, bodyguards as tanks, hitman as range dps.
I don't see the reason why there should be new stat in the game. Since every class has its equivalent on the other side. Why not make third party with same stats?
Wrong time period for the Vong, except for a rather obscure quasi reference from the original KOTOR games, they don't belong in the Old Republic and some serious retconning would have to ensue to explain their appearance.
EMPIRE CLASS - Mandalorian Raider
subclass - Mandalorian Gladiator (tank/dps) - uses heavy armor and large melee weapons, like the axe Mandalore uses in KOTOR2.
subclass - Mandalorian Scout (dps/healer) - uses light armor and a vibrosword.
REPUBLIC CLASS - Echani Monk (look the Echani up on Wookiepedia to learn more about them!)
subclass - Echani Sun Guard (tank/dps) the mirror of the Mandolorian Gladiator; uses heavy armor and double-bladed vibroswords.
subclass - Echani Duelist (dps/healer) mirror of the Mandolorian Scout;; uses light armor and fist weapons (since the echani excel in unarmed combat so well)
The Mandalorian would feel way too much like a BH except with melee weapons. I like the Echani idea, but you'd have to be careful with the Echani Sun Guard name since they eventually became enemies of the Echani from the other Echani planets, served Darth Plagueis and are the progentiors to Palpatine's Imperial Guard.