Really great work, you are a master with terrain and has so many great ideas. regarding the figures then I do think that they miss a little shadow. I did use the two washes (Black and derwish brown) from Games Workshop on my latest work and this is actually working really great and is simple to use. I will upload images as soon as possible.

Another fun thing to try could be the "The Army Painter, quickshade" which is a paint which you dip the figure in and let it dry. this should give a good shadow. I would recommend the one called "soft tone" as the others are too dark in my eyes.