Only thing I could think to suggest is to try and add smoother more natural transitions between the gaps in the rock formations.
From the pictures they look a bit too spacey and odd. Maybe smooth them out with a bit of gap filler to give it a more natural flowing look.
At the moment it looks a bit harsh if you get what I am saying.
Maybe once the sand and basing is added I will not see the problem anymore.
Personally I am not always fan of cork hills and rock formations so it is more a matter of opinion.
Although it looks good when done right. Which I think you pretty much have.
It can also be done very wrong
IMO.
May I suggest something for future reference or you may even like it enough to use it here...
I understand completely if you had no Idea what I meant by all that^.
I have trouble understanding myself at times...
Disregard this comment completely if it confuses you.
Most important thing is that I think right now what you are planing sounds good and it looks great at the moment.
I will hold most of my suggestions until I see it coming together more It is fairly bare-bones at the moment.
As right now there is only so much I can say...
Will try to keep an eye on this...