SH4 contains many role-playing elements, like crew names, medals, promotions, individual morale status. In my opinion it is up to the player how to use them. When I play SH4, I try to pay attention to these things, e.g. I will try to remember the name of a crewmember who got injured or of the officer in charge of important repairs, and they will be on top of my list when medals are to be distributed.
So no, I don't think SH4 needs more role-plaing elements, they are already there. If you want to do without them you can just ignore them, but if you want to use them, you can
Of course there's always room for improvement, like the captain's log that was suggested (I like the idea!).
The only thing that really limits the way I feel about my simulated crew is the lack of crew speech. If my officers would give an audible acknowledgement of all orders, or if there would be some more random background speech (like cries when the boat is being damaged, coughing when there is a fire) I would have a much better feeling that I am in a boat with "real" people.