The latest experiment on the way to finding a balanced solution between Red's design, Jordan / Emily's worlds, and Maya's output. Some of the things that have been considered are...
All objects (including Red) need a subtle noise pattern. Red's black outlines need a noise pattern subtracted from it. The background and floor planes will also need a noise pattern. In the example above noise has been added in three ways, on a light, using an image in post, and part of a shading network.
One possible solution to capture the sweet spot between Red's outline design and Jordan / Emily's drawn worlds is to limit the use of line work to single outline around each building. This will mean the inner detail is generated by a mix of ramp shaders, lights (with gobo's / gels), and a grain light.
A rim light can help separate Red from the buildings, and the buildings from the background. Both of these also stylistically help mimic light wrapping around objects too.
The backgrounds should be simple and abstract. In the example above the background is still possibly too complicated. However, once all the buildings are in place and there is a skyline this will become easier to judge.
Depth of field:
Although this hasn't been added to the image above its likely that as the world grows depth of field blurring will be needed to create depth.
It's still not quite there yet but its getting closer.