I've noticed two strange things, and I'm not sure if they're intentional or not, but here goes:
1) After I founded my kingdom, I'm having issues with joining battles. It seems that when I join a side that already has multiple armies, the numbers that show up on the battle screen (the one where you choose whether to fight, autoresolve, etc.) are way too low. I think that it only counts the soldiers in the first allied army plus your own. I think that the soldiers who aren't counted on the battle screen are still in the battle, but they're not counted for battle advantage (and probably not for renown). I know I'm saying "I think" a lot, but I'm not really sure what's going on, only that I'm often told that I only have 150 soldiers on my side, when I should have 300. This didn't happen before I became a king.
2) I helped a band of outlaws who were fighting my arch-enemy, the empire, which made my relationship with the bandit faction go up to -1 (maybe 0, not sure). Anyway, all outlaws, bandits and raiders on the map attack me on sight, even though I often outnumber them ten to one, and all my troops are top tier, which is annoying. Again, I'm not sure if this is intentional, but it seems odd.