Expand the X-Lines brand to cover all express buses in the North East (despite my preference for route brands, I do think the Xlines brand is good) and make some of the express routes actually express.

X21 for instance, bin off most of the stops between CLS and Durham.
I'd also make it pick up only at Gateshead and Low Fell to stop those lazy buggers that use it from Newcastle, taking seats from people who need to use the X21 to get further afield.

Actually, on a similar note, I'd probably introduce a priority system for people on long distance routes, so people travelling further get priority over those using it for a short hop.