A thoughtful & interesting post, Phil.
When I wrote my SYW rules, I used a Simultaneous mode. Our new Napoleonic rules (‘General D’armee’) use a fairly rigid Igo-Yougo.
Both sets produce enjoyable games but one aspect of the latter system I like is with firing. Unlike in Simultaneous where both sides shoot before casualty removal, G D’a has the advantage of getting in your volley first, devastating your enemy & only receiving a limited volley back in return. Most satisfying….if you’re on the right end of the Firing turn.