Really like the way the game play has developed with these set of releases, couple of thoughts:
The upkeep of fleets, does their maintenance/support ever alter when in port? My thought being it should be lower.
Also could they be damaged from extended periods away, such as settlement building being sabotaged, and so need a refit from a home port?
Also ( I know you mentioned this before but I can't find it) what happened to storms at sea?
Finally - would you ever look at armies surrendering/capitulating after a siege rather than the futile sally forth? I have only seen this once when besieging a village, with a small rebel army occupying it and outnumbered by 170%, but never in a settlement siege?