I'm sure snow has been considered.
I was just thinking of what Consumer Reports had to say about Japanese and American cars back when Japanese cars were beating American cars in almost every category. There was one area where American cars continued to be superior to Japanese cars and that was in corrosion resistance. All American cars back in those days were designed in Michigan which salts the roads in the winter. Because the design engineers lived in that environment, they gave better consideration to protecting the cars they designed from salt damage. Because the Japanese engineers didn't live somewhere where salt on the roads was an issue, corrosion resistance wasn't on their minds as much as the American engineers.
Tesla does all it's design in a place that doesn't get snow (except for a couple of freak times in the last century), it's possible they overlooked something engineers from a snowy climate might not have missed. As someone who has done a lot of software designs, there is almost always something you didn't think of that becomes obvious when someone in a different situation and mindset sees it. That's why you do extensive testing, but even then things slip through.
Nobody will know for sure until some people live through some winters with a Model X. It may be completely thought through and no problems, or something might crop up in the real world. We just don't know.
