You did it, Lilura. That was the most comprehensive summary of Brytenwalda I've seen, hands down.
Now, I'm sure the reader (at least, those familiar with Warband) can see what's on the horizon for me, gameplay-wise: A HEAVY, EXHAUSTING & REPETITIVE GRIND.
Not quite true. It would be a grind for you and a number of players, but it really depends on the settings you're using.
I remember having a considerably large kingdom once, three towns and a bunch of castles. It was getting harder to expand due to the failing economy, lack of defenses, incompetence of heroes-made-vassals, and the overall political situation. Most nations were allied against me. It took one battle gone wrong, my char was imprisoned, my companions fled and scattered across the world. By the time I broke out of jail, my kingdom was reduced to a single town and some backwards castle. Needless to say, I lost them too soon after that. Took me a while to find my companions and gather a new company from scratch.
I find the best, most reliable approach to this mod is take the warlord stage slowly. If you spend some years fighting in wars as a mercenary, you can reduce the number of kingdoms from 30-something you have at the start to 10 or even less. That makes the conqueror stage much easier, especially if you manage to ally with some of these leftover kingdoms. If you rush the conqueror/kingdom stage, you'll get ganged sooner or later.
In your review/LP of Brytenwalda you did a damn fine job winning battles against all odds. In the game though, if you only rely on your own personal army, it takes one defeat to lose it all.
Admittedly, there are a few aspects of Brytenwalda that I have not covered, namely naval warfare and diplomatic take-overs.recently.
The only thing worth mentioning about naval warfare is
avoid. Avoid like a plague. They never managed to finish this feature and moved on to this other modification, what was it called? Viking Conquest or smth. Naval warfare in Brytenwalda is buggy as hell.
Diplomacy is basically vanilla + a bunch of mods made by separate groups and integrated into Brytenwalda.