It seems like a really good start (regardless of your reservations on the shape of Seria).
If you are looking to try using textures to create the terrain (something I do lots of), I recommend you check out the free Genetica Viewer from Spiral Graphics. It has a good amount of textures of various kinds that can manipulated to some extent and then exported for use in the various graphics programs.
There are lots of other great texture sites out there, and I believe there may even be a list here somewhere, in the mapping elements forum perhaps?
Looking forward to seeing what you come up with.