if the cable/wire was not problem the exploration would have been done,they would need send recevier and transmitter down to bottom then use radio controlled ROV [if ever those exsist] it would be really nice if hard-to-explore areas would be finally explored,ROV tecnology keeps progressing and they eventually get best one but wreck dont have much time left.
Cameron managed to explore engine room and reach the WTD to turbine room but the WTD was closed and full of debris so could not go more.... why they did not try go around and use ripped shell plating as access point to enter compartment?.
i am wondering what happened to engine telegraph in engine room, heard it was mounted on one of engine colunns but the telegraph was never found,only bridge telegraphs were found and one or two recovered.