Overall, I quite like the proposed changes in Sunderland.
If the 56 regularly runs in twos or threes, as is often reported, it makes perfect sense to drop the frequency to improve reliability and consistency.
Whenever I've observed the X36 around Newcastle and Gateshead it's usually carrying very few passengers so a reduction in frequency was probably forthcoming at some point.
Although I don't live in Sunderland, I suspect that the cross-city links will be welcomed by passengers. Stagecoach seem to rather well so there's no reason why GNE can't achieve some level of success by doing the same thing.
The amalgamation of service 71 into proposed service 36 is interesting as it almost recreates the original route of the 71 with an extension into Town End Farm. Residents of Fencehouses will be pleased with their reinstated link to Sunderland.
RE: GNE Bus Changes.