I'm considering how to break apart the word "Shattrath" right now. See, "rath" and its cognates actually means home in a couple different real languages. And starting it with "tt" is just... inelegant. I know wowwiki did that to avoid the obvious of having "Shatt" or "Shat" = Light. I can understand that. But unsurprisingly, they are not taking noun declensions into account. If Shattrath is "Dwelling of Light" that means the "Sha" half of the word is likely to be genitive (think of that as being possessive or "of X"). So it is entirely possible that the root is "Sha" and it's declined to Shat or Shatt as genitive. I used "-as" for feminine nouns but it's not out of the question for it to be dependent on the letter that follows.
Using that root and theory, that makes the word for Light "shar" and the word for home "trath" or "rath". I am not entirely satisfied with that but it IS the only Draenei word that ends with "th" so I'm just going to write it off to an irregular noun (for now).