It's a shame that there's not space for a station at the triangle near the wonderfully named Hartburn, where the lines from Middlesbrough/ Hartlepool/ Eaglescliffe meet - a station there would also regular interchanges between the routes in the area, rathe than just relying on less frequent direct services
Logically, I agree
BUT, Teesside seems to be Westminster's second favourite place to spend public money (after Manchester) - the Tees Valley Mayor has had a lot of "good luck" in finding public money for the Airport, the old British Steel land, the Treasury jobs that are moving to Darlington, the "Freeport" status etc... the Chancellor's constituency is just a stone's throw away over the Tees... I've suggested it before but politically the suggestion of electrification from Bishop Auckland to Saltburn would tie up a number of "Blue Wall" constituencies and show some reward for voting Conservative...
I wouldn't be surprised if it was to be "heavily rumoured" in the months before the next election, with a blunt suggestion that this is the kind of thing only on the table if people vote the right way (some Tory leaflets have been pretty overt in suggesting that some public spending would only be available if their party won a seat)
That's not to suggest it should be a priority for the railway, but Bishop Auckland to Saltburn is a pretty self contained set of diagrams (obviously it shares tracks with other services, which is part of the reason for spending so much money to try to segregate it at Darlington, but the services are fairly independent other than token morning service from Teeside to Newcastle)
And then, once you do that, the case for the Durham Coast looks a lot better (albeit with complications caused by the Metro)