The Succ Mage, huh.

There [i]are[/i] unique classes that exist between nations, but there are also overlaps between classes, at least from a completely mechanical point of view. All nations have some access to the ocean, so it's possible to become ship boiz, but only Velonta would have easy and frequent access, as well as consistent necessity for such classes. On the other hand, Alderamin is the one nation that has self-propelled armored vehicles for purposes of blowing shit up. However, while Deneb is on the opposite end of the tech, you could still go for that sorta 'long range, anti-fortification bombarment' feel by buying/making magical siege weapons, such as the ballista or trebuchets, and summoning ghosts or fairies or whatever to man them for you while you sit on a self-installed sofa chair on top of the weapon.

So yah, vibe is right.