I’m on my fourth playthrough. Jesus Christ be praised!
I usually have a long list of wishes after so many hours but to my surprise I noticed my list of suggestions thinned out the more I played, to the point there is nothing “new” I’d add.
But there is one thing I’d like to have “more of” (DLC?).
I think 50% of realism is the world-building.
NPC-to-NPC interactions like trading and talking to each other and giving money to beggars, they are great but there are only a few types of dialogues, I’d love a few more.
More spawns in the world, more travelling groups, more bandit camps etc, but especially caravans - they add a lot of realism.
NPCs talking current events or even just the weather or playing games.
Children and dogs / cats chasing each other. Bar fights. Guards searching NPCs.
The ability to replay dates too (with some dialogue variety).
I can play 3 more playthroughs with that! 
Thank you for this game and I hope everyone else enjoys it too!
On a side note, my family has a 1500 years old Lombard heritage and we still live in the land we had settled in year 526. We have a lot of remains, museums, and do re-enactments.
But we knew very little of Bohemian history, it’s so niche and unexplored, yet SO interesting and similar to our history in many ways.
I respect Warhorse a lot for letting me experience the Czech history, I can’t wait for the sequel (I read the history books, but playing it is another story!).