It's a tricky one
On the one hand, for a lot of journeys, it works as a simple half hourly service pattern (without necessarily being much use as a combined ten/fifteen minute frequency) - there probably aren't any additional paths into Leeds or scope for grade separation or to do anything about the three single track sections (the Bradford - Keighley curve at Shipley, the line from Shipley to Guisley and the line from Apperley towards Guisley) - so there's not much you can do which would be "radical" (other than debating whether it'd be more efficient to interwork services or try to have stand alone ones, which may be more reliable but would mean additional stock and longer occupation of platforms at Leeds etc - mind you stand alone diagrams would allow more focus to be given to the busiest bits of line)
I think that the "biggest" priority I'd aim for, if trying to tackle things would be the Leeds - Keighley market, given that this seems to be the busiest bit of line (certainly a lot busier than my experience of Leeds - Bradford services or Bradford - Keighley services). It seems a shame that connections at Shipley don't allow many passengers to change from a Skipton - Bradford service onto a Bradford - Leeds service, since that would take some pressure of the Skipton - Leeds services (or at least connections were poor last time I was at Shipley - apologies if this has all changed during Covid, it's hard to keep up sometimes!). But even if you could flight services so that the Leeds - Bradford service was just behind the Leeds - Skipton service, so that it arrived in Shipley before the Bradford - Skipton train, you might have to add on quite a few minutes to allow people to get over the bridge, in which case it might not be competitive enough to entice many people off the direct trains
The idea that I couldn't get to work was a half hourly "fast" Leeds - Skipton service which would be mainly EMU operated but would include the Carlisle/ Lancaster trains as well as potentially some five car extensions of London - Leeds services (in line with the Harrogate extensions of similar trains - a "London" train should be stopping at similar intermediate stations to the Carlisle/ Lancaster trains) - but I don't think there's space for such a service - which means we are in the awkward position of the Carlisle/ Lancaster trains being short 75mph/90mph DMUs taking up scarce paths outside of the clock face half hourly pattern - you could insist that they are combined into a single bi-hourly path between Hellifield and Leeds but would that make it less reliable? I don't think it'd be acceptable to cut them all at Skipton, but otherwise you're forcing passengers from Bingley etc onto the short DMUs - unless you make the long distance trains non-stop south of Skipton but that would have similar problems.
You could theoretically make Leeds - Skipton a fifteen minute EMU service, by removing the services from Leeds to Bradford and Bradford to Skipton and replacing them with additional Leeds - Skipton services, but that certainly wouldn't go down well! Yet how else do you focus on the busiest flow without cutting something else?
