Battles are the core yes. But marriages should be second. At the time it was huge. It was how peace was often made and alliances. It was a core of politics. Many times more of hostage situation.
One can let the ai fight. I think many do. And the player walks around feif managing. High in charm and one got both 5 in loyality and 5 in security.
Relations with marriages should be the focus after battles. And battles are great in the game.
Rougery and smithing are for me useless features. My game is so modded right now that when i even press smithing the game crash. And i am perfectly fine with it.
At its core it is a battlesimulator with some strategic and RP elements sprinkled on. Its not a dynastic game, its not a grand strategy game and it is (most certainly not) a medival merchant simulator. Their are simply much better alternatives to all these genres out there.
Its primary claim to relevance is that you can fight some relatively large battles (Total War) with the twist that you can personally participate in the action. There is simply no point playing this game, over other and better alternatives, if it is something else that you really want out of the game.
My personal view, is that Bannerlord, at least on the forums, get way too much flak for things that are largely immatrial (that includes, the dynastic aspect; its there, people can play with it if they want but it is not fundamental to the game). People simply have unreasonable expectations as to what the game really is.
Anyway, its just an opinion.