My favourite types of topics - feature request time! 
It is possible to make realistic results with Cycles that will spar with Corona Renderer. Besides that compositing, good textures, details (wearing, dirt), lighting setup and etc. are important to achieve realism, what Blender and Cycles are missing are things that will speed up production - I wrote about it once, lighting is almost the same because all renderers uses the same or similar equations and they are approaching the same results as in real life (what differs engines the most is shading but it would be better with Principled BSDF V2):
Archviz guys are always pursuing for goal of creating most appealing and realistic scenes, so what they do, for examaple, is saving renders as EXR and putting them into Corona Image Editor. Corona has really ease to use (and faster!) tonemapper with features like highlight compression, loading LUTs, physical glare and bloom effects, with custom bokeh effects. Other artists use K-Cycles or Octane because of this (art of Jan Morek made in Blender + Octane):
Blender doesn’t have dirt shader, triplanar, auto vertical camera guessing, archviz glass, basic assets, better microdisplacement, LIGHT LINKING etc. - it is possible to make those things by user, but it’s a tedious work and I think that they should be built-in. These are small things that add up to a big picture.
With new developers things are going for better - there will be Project Heist that put emphasis on realism so artist from Studio will need new tools. There’s Principled BSDF V2 so shading would be far realsitic than current; Real-time compositor would speed up looking into end results; also caustic solver and path guiding would bring some significant speed up. Filmic V2 aka AgX is going to change for good look of our renders.
