Some Coastliner Suggestions...Malarkey Marathons as some in the past have called them.

X40 - Leeds - Tadcaster - York Rail Station - Malton - Scarborough - Cloughton - Whitby
Limited Stop Express Service connecting key points of the route only, operating Every 1 Hour Monday to Sunday providing a reduced journey time across the whole route

840 - https://www.google.co.uk/maps/dir/Leeds/...283113!3e0

843 - https://www.google.co.uk/maps/dir/Leeds/...486335!3e0

In regards to the 840/843 from Malton I'd have them do Clockwise/Anti Clockwise Loops of Pickering - Goathland - Whitby - Robin Hood's Bay - Cloughton - Scarborough - Seamer and Sherburn back to Malton returning to normal route back towards Leeds allowing connections down the North Yorkshire Coast between Whitby and Scarborough via Robin Hood's Bay which I think would vastly improve the tourism side of the service and give it a much needed money boost all round to keep commerically viable to operate, the services would also have sufficient layover time at both Whitby/Scarborough depending on direction of the loop.

Other suggestions:

Extend service 20 from Rawcliffe to Harrogate via Knaresborough which would give a more direct service to York than the 22/23 do, I would also extend services 22/23 into Harrogate from Knaresborough also