I don't think there is enough dark tone, the picture plan is cut into two parts, very light and mid tones. Cutting a painting in half like this is a bad idea, but not irredeemable. I could trim up to half of the sky away, which would remove one problem.
I could also go in with more inks, or perhaps technical pens, and add some darks, perhaps increasing the blue area in the centre and to the right, making sure that each area was a different size. It is also mostly warm colours, so by increasing the blue this would help to balance out the temperature.
I may do this, but this is an experimental exercise, not an exercise in making paintings, so I may not.