Thanks for your comments
I will darken the ground under the trees and the stones a bit. That should make them fit a bit better.
I have an idea on how to get rid of the texturestreching on the slopes (I know the way with a model but I am really bad at UV-mapping...), but have still some problems to realise it-.-
A day night cycle wouldn´t really work as it is now. the plants are lightened independent of the sun and the shadows would get a quite strange behavior (but id basicly work for them)
And no, I don´t have a gamplay/story/what ever for it yet...

About the grass and trees:
I think they are okay looking from the perspective they can be seen from by the player, just not from those I mainly used fr the screenshots.
Here is an other one showing how it looks for the player:


I will also use a brighter texture for the mountains.