(27 Jun 2022, 7:23 pm)streetdeckfan wrote I don't mind if an express service isn't limited stop, as long as they're infrequently used.

Take the X30/X31 for example, although it does technically serve every stop, in my experience it's very rare that it actually stops everywhere. You get a few people in Dunston and Whickham, but I don't recall it stopping very often between Sunniside and Stanley, at least outside of peak hours.

Despite that, the timetable for the X30/31 will reflect those stops. Removing them won't harm many, but would allow the journey time to be decreased and reduce layover/idling and potentially improve driver resource (yes a few minutes on one journey isn't going to make much difference, but added up over the course of a day/week/month, it will).
A bus ain't going to make money laying over or waiting time.

The 4 can be bad for that.
Sets off from Houghton towards Heworth and can end up laying over in Burnmoor for what seems like an eternity.
Ditto at the Galleries with the 4 and X1.
But the 4 on an evening or Sunday and its layover in Houghton can be there for 10/15mins.
The X1 at Dalton Park isn't an effective use of time either. Despite the connections it opens up.