Have replayed this now after a long break. The thing I love most about Sovereignity is the tactical combat! Roads, mountains, hills, rivers(!) matter so much. Forts can be very strong defensively. Some regions can be very though to attack. But you can customize your army or you can try to exploit certain weaknesses of the terrain or the enemy's positioning. The game has a nice sense of progression in the way that you access more high value units over time. How gratifying to build up your dragon cavalry with the Dragonhold faction and use the dragon units to make long range charge attacks. But if you are to daring it could be out there for an enemy to kill!
Your units gain experience and you customize them for certain roles (defense, offense) or ways of combat (more range or more range attack for your ranged units?). You can't have it all!
Holding a territory can be difficult or easy depending on the kind of troops you have there and the enemy's units.
This time I have not yet experienced the AI combat bug. The Iron Barony was throwing it at me nicely just like in my first game ever.
Hot seat or multiplayer would really be a blast. Imagine those though tactical battles against a campaign-hardened player army!!! Would take forever until one side wins but it would be epic ;)

All in all I am at peace with buying this game. Got plenty of fun out of it.

I just hope the developers revisit the concept one day and give us something new with all the goodness of this gem.