While I am a big proponent for route branding, I can see why with the way GNE currently is, it can be a bit of an issue. Here are a few ideas I had to simplify, but not remove route branding.

Dedicated route branding, for the most part would go. With each area instead having it's own brand, similar to Sunderland District, except without the variants. Since I'm not particularly fond of the word 'district', they would become 'Locals'. So we would have Sunderland Locals, Gateshead Locals, Derwentside Locals, Peterlee Locals etc. All vehicles will have a blue rear, with only the front portion and the road stripe changing.

I would keep X-lines, but all vehicles would be in the generic charcoal allowing for flexibility in moving vehicles around. I would keep them 'branded' per route, ie. having the locations on the side, but they would all be the same colour. It would probably make more sense to have them in the blue X-lines since it would match the rest of the fleet, but the charcoal is nicer!

I would introduce a new 'Citylink' brand, connecting the three cities in the North East. These would keep the current unique colours, but be under one brand. Unfortunately that would mean the end to 'The Angel' brand, but I'm aiming to simplify the branding.
Citylink 21 - green
Citylink 56 - orange
Citylink 20 - purple

Longer distance, but not express, routes that cross the area boundaries would fall under the new 'Connector' brand, this would take over current brands like Coaster, Crusader, Connections 4, and Country Ranger.

I would scrap VOLTRA, at least as a main brand. Quaycity would be rebranded back to Quaylink becuase Quaycity is a shite name that is horrible to say. VOLTRA 53/54 would just fall under the Gateshead Locals brand, maybe with some Voltra crap on the side.

Here's a potentially controversial idea, Cobalt&Coast would become part of the X-Lines brand. The vehicles are of the right spec, and are arguably about as express as the other X-Lines routes!

Since I've obviously mocked up my ideas, I'll post them in the brand ideas topic