A side thing that'd be very cool for water races is the equivalent of the water-breathing army items for land races. I know the ring of the fish will allow for commanders to tread on land (which makes for a happy Aboleth) but I don't know of any items that allow aquatic troops to come ashore. It sure would make those other Water summoning spells (like Call Kraken) far more palatable, particularly on maps like Inland where 90% of your fighting's on land anyway.
If there's already an item like this, just clue me in and ignore my ignorance.