The Corsairs are very proud of their heritage, of who they are.
They're pilots, they're ship builders. Ask anyone what the Corsairs are, what their strength is - they'll say ship building. That's their national identity, that's where they get their pride. The distinctive and intimidating shape of a Corsair ship.
Corsairs won't use ships they don't make, it is said.
Thus, it barely makes sense for them to be using an Osiris, as much as they might need it. Within roleplay, they'd use their skills to modify the Osiris into a truly Corsair ship, add armour and guns as they love to do, and turn it from a lighter battleship into a heavier battleship for their uses.
(I realise that you all want to preserve the dichotomy between the Legate and the Osiris, I'm just speaking within the realms of roleplay more than gameplay.)
It would really make sense if they DID have a modified Osiris - otherwise, they wouldn't be flying it, because it's not a Corsair ship.
