I think having the manufacturers name is actually a good thing. The Android sister site seems to also do this and not have any synonyms e.g. https://android.stackexchange.com/tags/samsung-galaxy-s-3/synonyms and https://android.stackexchange.com/tags/htc-desire/synonyms
While I can agree that for Lumia it is currently obvious that it is a Nokia, for other manufacturers with short product names it would be less clear e.g. I think the synonym 8x should be removed, especially since there is a similar and unrelated 7.x. This might not currently be a problem for Windows Phone as it seems to just be Nokia releasing phones these days, but if more products started appearing with generic names it would become a bit messy.