Unfortunately i can't offer much specific help man, it's something i struggle with even more than you do.
Maybe try out some different exercises to get you thinking of envrionments in different ways? If i had to guess, i'd think you have the same problem i do with environments -- when you're painting an environment you have to really focus on defining the perspective/forms and it prevents you from freeing up and focusing on the composition, so maybe a really different workflow would let you bust out more creative pieces
This is really neat, albiet pretty expensive:
And this may be something cool to try out, i know jackwhat here uses these techniques a lot:
Lastly, and most importantly, if you don't already own it, get the skillful huntsman!
There's a video review down in the comments, the book will blow you away.