This is a tough question ...
I'm not really objective here because I tend to build larger and larger bases (who said dioramas?) For not some many minis so ...
And I have some ideas fro future project even "worse" in this regard...
Anyway, that beeing said, I think it's mainly an issue where you must not loose the mini in the base.
So, in that regard, I think you're base is doing the job as the mini is clearly identified and there is no doubt about that.
But, and this is only my opinion: I think the currently display is too bulcky.
Let me try to explain myself:
The mini is really cool and I love the pose. He looks really powerfull, for me it's not just a dwarf, it's a king.
Though, the global shape of the mini is like a rock, push to the extreme, we can see it as a globe.
So in order to play with that, I would have add more verticality to the scene.
I like you idea to place him in top of a mountain, contemplating his kingdom with pride.
The thing that bothers me is the right side of the scene. I think there is too much mass on this part, I would have incrise the inclination to really place him on some kind of estale foot.
Again, it's just my opinion.