Then Weber unleashes arc 2 on us in a few years time. What do we think the setup will include? Here are my thoughts (but as always, all characters, legal rights etc belong to David Weber and if any predictions do occur in the book, all I will say is "called it!")
1) Prince Daivyn - He's got a massive worship-case for Seijins and almost certainly will want to be one himself. As such, he will be a keen student in the art of Kendo and will often spar with Nimue, Merlin and Cayleb. He'll possibly become known as The Seijin Prince.
2) Steam power - RFC has indicated that railroads will spread across Safehold meaning that steel production will continue to grow (engine parts, rails etc). We can expect more foundries everywhere except North Harchong (too traditional) and Desnair (too anti-trade but has gold mines).
At least a dozen railway lines will reach Zion, allowing for more people to make the religiously-mandated once-in-a-lifetime journey.
3) Narhmahn gone. He's too good at ferreting out things and will tilt the stage too much against the Returned Archangels. We know he intended to shut down when his wife finally died... meaning we'll see his son mourning his loss once again.
4) Only one armed Galleon remaining in the Charisian Navy and that one for ceremonial purposes such as State Visits. Said Galleon will be an Ironclad one, though. All other ships to be steam-powered.
5) Earl Thirsk being appointed as Chief Military Commander of Dohlar in charge of all land, sea and possibly air forces. Dude deserves respect, he was probably better than Cayleb would have been without Merlin's aid.
6) Zeppelins. They've proved darned useful as tethered craft so someone will figure out a way to get a small engine aboard them to let them fly at will. Secondary air-bladders inside the Hydrogen bags will allow them to change the relative density and thus lift generated by the gas, letting them go up and down as needed.
7) At least a dozen King Haarald VII-class ships in the ICN with one or two of them being slightly modified to be the personal vessels for Cayleb and Sharleyan when they transition between capitals. Possible scene has Old-style Clyntahn-loyalists try to attack, only to get blown out of the water at range.
8) Prince Zhanhn joins the ICN or Army despite his wedded bliss in order to follow the tradition of service the Armahk family follows. Tends to find random Seijins pop up to tell him things that he really needs to know.
...and that's all the formed-enough-to-note-down expectations I have so far.
RFC will probably read this and fall over laughing or something at how I'm trying to predict him.
Heck, he got me good with the Major Phandys thing. I did not see it coming, but frantic backtracking through the other books revealed the hints that something was up...