Yeah, I was thinking roughly the same.
Except for the port taking damage but that is just another way to install repaircost ;-).
Only +1 move when moving strategically from a port (no combat during movement), not necessarily to another port, sounds interesting!
And yes guys, destroyers can cause damage to Battleships if operating together with heavier class ships. I still feel it’s more of an exception (and a rather heroic one) than common engagement as DDs without heavier support usually flee to a safe distance if they spot an enemy BB, or sacrifice themselves to protect a bigger prize, for example a crippled and fleeing friendly Battleship.
For the record: I was not talking about CAs or even BCs, however dreadful they might be. Not to mention the exemplary heroics of a DD crew engaging such heavy ships!