Its finding the balance between speed and generating enough revenue/custom to make the service viable.
They obviously feel Newcastle Road and North Sunderland is their best option, rather than sending anything direct via say the A19 and Felling Bypass (which would be quicker).
If enough people use the service point to point ie Park Lane to Newcastle, then it would be beneficial.
If the loadings are low from Park Lane, then the only other way to generate custom is for the service to operate as a local service upto a certain point and then an express for the rest of the journey.
RE: Go North East