I disagree strongly with your example Xei, how exactly are eskimos exposed more to form and space then us? I would argue that a dense urban environment poses a far more complex form then the sparse huts and great plains that are presented to eskimos in their lives.
I don't honestly understand whats so conceptually far fetched about language having a role in cognition. What is the primary medium that we manipulate information with? Language, whether we're talking English, Japanese or even maths.
I do agree though that this needs to be studied in more depth. A possible experiment to conduct would be to conduct an MRI scan on a native english speaker as well as various visual memory tests, then put him on a 12 month course on learning an eskimo dilect in which he continues to live in his normal surroundings. Then after the 12 months are up, test him again on visual memory and rescan him and compare the two sets of results. If my theory is correct, you should see a significent boost in visual memory as well as enlargement of the posterier pariel cortex as well as both visual cortexes. I'm fully aware of how sketchy a picture I've presented but you get the idea. You can adapt this basic format to test any language