More diagnosis render passes?

[iLEZ]

I know that I can use Albedo to find out if Corona is doing an unnecessary amount of work in blown-out areas.
V-ray has a pass called "Sample intensity" or something similar, in bucket mode, which generates a heatmap that you can use for diagnosis of your scene. It is very helpful and gives artists a visual feedback of what might be wrong in a scene.

I know that Corona is different and that you obviously can use the different lighting passes to check where the processing power goes, but are there more passes "behind the scenes" that we can use to see what might be taxing the renderer unnecessarily? I don't know what it might be, but it would be cool to have more render pass options. =)

[FrostKiwi]

Holy moly macaroni,
this sounds awesome and unique.
Just imagine, breaking the image up into 128x128 blocks, doing a median of total rays and samples per second in the block and comparing it to the other 128x128 blocks. The media of all would be blue blocks, below would be green fast rendering blocks and above red slow rendering blocks.
A heatmap for where your performance gets screwed - Just imagine!

[Ondra]

done