My view is that the Harrogate service is justified - it does seem reasonably well used to Harrogate, and it also happens to provide a useful express service on the Harrogate to Leeds section, as well as topping up capacity. It’s a lot more useful now it has a regular service. Running as a third train per hour, and avoiding reversal at Leeds by going via Hambleton would, IMO, be even more preferable, though this would of course preclude direct Wakefield-Harrogate journeys.
Middlesbrough likewise I think has merit as a regular service.
I’m less convinced by the one-trip-a-day extensions. These seem simply to tick a box, and involve a disproportionate use of resources to provide them.
I’d be tempted to do something like 3tph to Leeds, with 1tph of these going via Hambleton and extending alternately to Bradford or Harrogate. I wouldn’t bother with Huddersfield, as there aren’t the added benefits as the extra capacity isn’t useful at the times in question, and they already have a fast service. I’d only keep Skipton if there was data to show significant numbers of through-Leeds journeys. Sunderland I wouldn’t bother with at all.