the time scale is an interesting one: 68 years is a long time to be developing new technology especially since we know at least a few of the nations are investing heavily into archeotechnological rediscoveries and advancing in huge steps.
50 years sometimes isnt that much, sometimes its HUGE, so its hard to know if we are talking 500-550 AD levels of advancement where we are talking maybe metallurgical advancement, but basically the same thing. or like 1910-1965 levels, where each 10 years a revolutionary technology emerges?
we know the chaledonians for example were WAY late to the airship party, but have advanced at an alarming rate, so it may be that their rapid advancing might mean that they will be expanding a lot in the coming years. their borders are impossible to cross without air ships, and chaledon's air fleet reflects this truth: they are all light, agile ships capable of intercepting and outmaneuvering larger vessels and destroying them. short of huge fleets flying in formation, there is always a way to slip a few squids in there to cause mischief. nobody si gettign into chaledon uninvited with the airfleet zipping around
the arashi i would guess would be nearly impossible to invade even though they have incredibly valuable old tech ruins that they have used to create amazing new tech. i imagine that the desert is nearly impossible to march across with an army, so any invading party would have to be on airships. an ambush of 10 or 15 people hiding under blankets with artemis rocket launchers could destroy most ships in a matter of moments. this sort of attack would end any sort of raid.
its anyone's guess who will make the knockout discovery, maybe angleans will discover something game-changing and start conquering the warm and fertile parts of the world with indestructable metal soldiers. maybe the mercantile guild will crash the economic system of some of the neutral major cities and expand their hegemony. maybe the fjords will reach out and capture some land that allows them to feed their people comfortably and then use their surplus resources to hugely expand their airfleets.
who knows? that's why its fun!