The LBA - LHR link by BA worked well for many years because of good onward connections of course. BA pulled out because they wanted to upgrade from using Viscounts to jets. Leeds city council made sure they would not extend the runway at the time for jets so British Midland took over.
This was also very successful for many years and I seem to remember flights peaked at 5 per day.I am not sure how BMI onward connections compare with BA but I would assume BA could make it work better than BMI these days.
(Leeds City Council continue to try and stifle development at LBA with the new owners struggling to make progress.)