Interesting, however I feel like you're kinda making a mistake in doing a "true" representation of FE4. Here are my ideas on how to tackle the two Jugdral games; I realise I'm just another smelly internet user with another smelly opinion, so feel free to go your own way about this.
1. Take inspiration from Fire Emblem 7, and let there be three paths; Sigurd's path and then Seliph's path and Leif's path.
2. The best part of FE4? The gargantuan maps. The worst part of FE4? All the traveling over said maps. So, is there a way to fix this? Why, yes, I believe there is.
First, the game should have the map stitched into it's entirety. There is one project out there that has attempted this already: https://feuniverse.us/t/the-jugdral-continental-project-finished/8551/42 This way, the illusion of grandness would be kept, while still allowing a more traditional map by limiting the scope for each map.
Second, each castle seize should be it's own independent mission. That's not to say each and every map should be a seize map; while those would be the main objectives, some secondary objectives are also interesting. For instance, a couple of defense maps and so on.
Third, given the humongous cast (24 characters each generation), there should be multiple deployment options. Take chapter 2 for an example of how this can work;
- You start with the first map centered around Nodion, where Sigurd says "we ride for Nodion, immediately!" and then you have a cavalry-only map until the foot units can catch up.
- From Nodion, you could have the Heirhein siege/sacking, but at the same time as you send units to Heirhein and subsequently on to Anphony...
- You could send some units up to get supplies in the villages, where they of course encounter the bandits and a certain mage.
- Then this group would have to deal with the Augusty counter attack sent to destroy Nodion...
- While your new mage catch wind of a planned assault on Evans, routing another dispatch there.
- Finally this dispatch is sent as a strike force to take out the ballistas in the mountains while Sigurd returns to Nodion and marches up to Mackily.
- All converge then on Augusty.
I feel this allows for quite a few more dynamic exchanges, keeps the spirit of the original as well as avoiding the boring "Must-Travel-From-X-To-Y-To-Z" parts of the original. Just some food for thought. 🙂