Well I have some troubles using filmic too.
It works great to give you a great look in medium tones and with default parameters.
But when I have skies with clouds with billiant lights (and a bit overexposed in some places) I don’t get very good results. It tends to make skies dull and I want a bit more dramatic effect.
It is understandable to some point as any S curve or contrast curve will give you contrast in midtones at the expense of compressing highlights and darktones.
But It was easier for me to expand lights previously using curves or other tools.
With filmic I do not find easy to do that even if I am using color balance to expanse highlights (and apply it only to them with parametric masks).
There are many options in filmic, it does lots of things at the same time and I cannot understand all that technical stuff (even if I have read it several times in the last year, from version 3 of filmic, but it is getting more and more complex each version).
Here is an example with a raw photo of mine.
I have used color balance to tweak highight, midtones and darks separatly, some local contrast, contrast equalizer, and so.
I have upgraded the edit to use filmic v5.
Here is the raw (of course you can download it and play with it):
Creative Commons — Attribution-ShareAlike 4.0 International — CC BY-SA 4.0
DSCF0262.RAF (23.9 MB)
This is the xmp with edit.
DSCF0262.RAF.xmp (17.2 KB)
I will try to edit it using DT 3.7 and color balance RGB instead and the new diffuse module to make the focusing and debluring.