It's a pity that you don't do anything with your images after they come from the camera; you can improve on the contrast, adjust brightness, repair colors, bring forward details that would otherwise be obscured, reduce noise, remove undesirable artifacts, etc. Shooting in RAW and editing in 16-bit increases your editing headroom.
There is nothing unpure about fiddling with your image afterwards; you already "edited" it when you chose your exposure, white balance, color space and JPEG compression.
You don't need to use Photoshop, but a program such as Aperture, Lightroom or another RAW converter with extended capabilities would be very useful.
As for your specific images, my opinion is that they are a bit too gloomy.
The one with the tree is the less gloomy one, and you have a promising theme going with the contrast of the tree, the glowing clouds and the low clouds or fog. Unfortunately, it is a bit unbalanced, perhaps including more of the hills and foreground could help.
The horses in your other picture form nice silhouettes, as do the fence posts. I find the hill sides rather boring and uninteresting, and the far brighter sky distracts from the foreground. Here's a couple of examples of alternate representations:
But don't take my word as gospel.