Let me discuss both points here.
3D work being done in a way that resembles 2D painting, but with the advantages of 3D
We are already seeing the possibilities of this with the likes of technologies like Ptex, the advent of Ptex means we can texture meshes, both simple and complex without UVmapping. How could it make a work-flow similar to 2D painting from start to finish.
Simple: The possibility that with enough of a painting system, you can just remove lights (or have a very basic setup), and using Ptex painting to create fake shading complete with fake highlights and bumps as well as light and shadow.
Rendering would be very quick as there’d be no complex shading and doing multiple angles can be done without having to start again from scratch as so in a 2D program. The downside may be due to having to paint reflection and refraction effects in the camera view per-angle, but this workflow may be possible in Blender in the near future without the need for an external renderer.
Setting up a scene and lights like a 3D variant of photography.
This possible future workflow is being done through the likes of the race to create professional-grade unbiased renderers like Lux, Indigo, Octane, and in some cases the new Thea renderer.
The promise of unbiased rendering is this: Set up the structure of your scene (perhaps even using scripts to ease creation of various items), give them materials and textures, and place lamps and emitting meshes where lightsources would be, render for as many hours as needed, and you have an image that looks as if you built it in real-life and took a picture.
This could allow: Instead of artists working like a technical department trying to find the perfect places to have bounce lights and caustic lights, the artist works more like a photographer not having to have any in depth knowledge on how to make a light rig that resembles actual light physics. Caustics and indirect lighting come by default and there’s no hassle over whether that bounce light over there is too far to the right, needs more power, needs another lamp nearby, or needs a color/falloff tweak.
The best news for us users of Blender however is that we now easily have that option because of the 2.5 rewrite (because of the fact that exporters like LuxBlend25 can replace the UI panels entirely instead of being largely restricted to a special scripts window.)
Right now the main disadvantage is sometimes you have to tweak the GI settings quite a bit to get good, noiseless lighting, but could be resolved with better defaults out-of-the-box.
Your thoughts?