Being a tugboat man myself, I would LOVE to see more bargework and more realistic and classic tugboats, like the ones seen in NYC today. The tugs in SS08 are underpowered and styled like tugs I have never seen before.
Shifting oil barges is the main maritime activity in NY Harbor today, and doing such operations requires a lot of seamanship and boathandling skills. Putting a tug in the notch with pushgear, towing it, or putting it on the hip and transporting it between NJ and NY terminals would be a really nice challenge.