Man, Brytenwalda v1.0 is one of the greatest M&B mods I ever played, and I've been playing M&B since 0.960...
A few problems I encountered so far:
Inka have her birth city set to Player Faction.

Wandering Bard have some problems cropping the text.

The name of a faction disappeared from the Relation Screen.

In the Known Lord screen, still appear the Calradian names of the factions.

A couple suggestions:
This is more a Vanilla issue, but it could be nice if the Lords give some quests only when on high positive relations with the player. Like the
Collect Taxes one, I think that no Lord could ever entrust such task to the first person they meet (and I think of this quest as a exploit too).
Also, I think that the faction of choice at character creation should give a starting relation level with all factions in the game. Like a Pict player having +5 with the Pict faction and -5 with all the others, or so (I'm not an expert on that historical period, but you know what I mean).
The same could go for Companions, they should only be hirable by players they have in good relations with (or neutral at least).
A question: How do
Salinae works? Put I slaves to work and every week I receive some money? Do they have a escape chance if I don't assign guards to them?
Two more: Do
Surgery still works when
Realistic Casualties is ON? What
Dissable drowning in missions stand for?