I 100% agree with the feeling on an in-engine vertex painting solution. The cgfx pipeline is not ideal but I can see accurate results in Maya prior to export so it is not a complete dealbreaker. I also have a tutorial on that if you wish to check it out regarding blend layers in the engine.
As for the comments on textures I am not exactly sure your approach is correct in terms of your look. Seeing as how CE has been physically based for over a year now you should not be hopping back and forth due to subjective feelings on a texture accuracy. I don’t have this issue due to following pbs best practices and dialing in the spec color term in the material dependent on the material I want to create. The albedo map should be set properly externally and if need be at the end you can dial the diffuse multiplier from 255,255,255 down to a level you find appropriate for the finalized comp. I do suggest against this though to have accurate textures across the entire scene.
To comment back to Max Dev and the overall look you could state the same for UE4 as well. It mostly deals with the lighting solution. Using color grading or even TOD post processing as a post effect can minimize this look. One thing I will state is I wish they would open up some sort of toon shader to the build in order to accommodate more variety.