Hello, I was curious whether the difficulty levels have been changed in this mod. Back in the base game I remember anything higher than Captain being ridiculous, especially the land-battles, particularly the quest related ones.

Also has the AI of enemy ships been improved in any way, for example: switching to cannon balls once they don't have the range for bombs etc.?

The difficulty level is unchanged for any of the COAS-based mods, so it is still rather ridiculous at the high levels.

The AI of ships is mostly script-based.  The only engine modifications are that when the script tells a ship to flee, they will usually take smarter paths away from threats in Maelstrom.  COAS script AI is unchanged.  GOF has some modifications where they will switch ammo a little smarter, but if they run out of ammo or powder, both COAS and GOF will continue to "fight" without ability to even fire.  For ERAS, the ammo switching is a little smarter with the added feature that if a ship runs out, they will attempt to flee the battle.

Also for ERAS, there are a few quest points that were modified to make it a little less brutal at higher levels.  One case is the fight in the house during Isabella, where a short delay was added before the enemies spawn, to give the player a chance to position better, since the enemies are so fast and powerful and they quickly surround you and dead...

Another one I know that was modified is the Esmerelda shore where there are something like 10 enemies and none of your fighters can spawn there; if you have fighters, they will spawn, and at the lower levels, if you have no fighter support, not as many enemies will spawn.

In short, not much has changed, and I tend to only play at difficulty 7 or below because the original was not very balanced.  However going through the entire mod code to adjust all situations and quests is too large a task to address as a solo developer that also has a day job.