Let me start by making two things perfectly clear (doing my best Nixon imitation here):
- I am not a "purist" in that I feel a photograph should accurately reflect the scene as it occurred naturally. I feel free to interpret the image as I want the scene to look. There is no right or wrong answer on this, but I gather some of the folks may not agree with some of what I suggest - that's OK.
- I know absolutely nothing about Gimp - no clue what it can do or how it does it, so I am going to try and offer processing suggestions as generic as I can. However, keep in mind I have been a LR, Nikon NX2 and Photoshop user for many years, so that is what I know.
OK, mouse print out of the way.
I gather you pulled down the high tones and pushed up the lower tones. My first observation is that there appears to not be any more detail in the clouds that Gimp can recover, so all you have accomplished is to reduce the contrast (bad) - I would nix that adjustment and go back to the original. The shadows appear to have had a bit to offer, and while the contrast is further reduced, there is information in there (good).
One thing to always remember is that trying to recover/extend dynamic range by messing with the LR highlight/shadow sliders (or Gimp equivalents I assume) reduces overall contrast. That eventually has to be restored or the image will look really flat and dull. This is a bit of what happened to your remix attempt. However, I suggest doing the color corrections first before trying to fix the contrast.
The first thing I would do is address the color. I would first try setting the WB with the eyedropper (assuming Gimp offers this) on one of the featureless cloud areas (presuming it should be white) and see what that looks like. It may fix one or more of the issues below:
- the dirt field is both a slightly odd hue (at least based on dirt here in the US)
- The blue sky in both versions is a rather unattractive grayish blue, especially on the left side.
- The road is a little bluish (not unexpected with shadow areas)
- The hedge in the sunlight on the right and the stand of trees is a little warm for my taste
Correcting all of these will require one or more color range specific adjustments likely using something like the HSL tool in LR.
Once the color is sorted, I would add contrast via Levels & Curves. It certainly appears in the 2nd version that the black point is elevated above the clip point - fix that first. Then run the white point just shy of clipping. Last, introduce midrange contrast by putting a bit of an "S" shape into the tone curve.
Another useful tip is you can add local contrast (which looks a bit different than global contrast via levels or the Contrast knob) by running an Unsharp Mask tool "backwards" Instead of large Amount and small Radius, use a small Amount and large Radius. The result is similar to small-moderate Clarity settings in LR.
Let's see where that gets you assuming I haven't totally confused you
I apologize if this seems like drinking from a fire hose.
Oh, and it would be very helpful to know if we are shooting NEF's or JPG's.