I played this mod yesterday and today as Union. It is really well done and a lot of fun. Congratulations!
I do have some suggestions. Being able to research to Naval tech Level 5 seems really high for this time period. There is already a nice difference between Monitors and Cruisers. Perhaps limiting Naval Tech to Level 1 or 2 would be better.
In the 1860's, one only traveled by foot, horse, train or ship. Being able to research Mobility Tech seems out of place.
Artillery didn't change very much during the 1860's also. I would suggest limiting Artillery Tech to Level 1. Artillery was very effective defensively, but not this effective on offense.
I wonder if it would be possible to create Union Gunboats. They would attack at range like Armored Trains. Such ships would be fun on the Mississippi River.
Thank you for creating such a wonderful mod.
First off, thanks for playing the mod and I'm glad you're enjoying it
As to your suggestions:
Naval tech - never really thought about that other than "iron ships beat wooden ships" and possible improvements in naval organisation, but yeah I totally see the argument. Though I've never seen the AI research it (it has been programmed to but tends to have a lot of other priorities), and I never really bothered with it either in my billion test games, so it is probably not that big of a deal.
Mobility - I've always thought of it as a combination of improved tactics (such as Lee and Forrest running around without the Union knowing about them) and stuff like giving units more horses. Doctrine upgrades, that sort of thing.
Gunboats - you can, that's why the Mississippi and Ohio are navigable: purchase a cruiser or monitor and deploy it at an inland port.