No one's asking for a full-on Tolkien treatment with a reference grammar and writing system--not to begin with, anyway. I think the main thing we are asking for is that some thought be put into the structures of the setting's various languages so that, say, names and place names make sense and are consistent. One of the immersion-destroying things that can happen in a setting like this is that names, words, and phrases are created haphazardly, leaving the player with a strong sense that what he or she is dealing with is just a palette-swapped English. Worse, the setting can import existing alphabets and languages (the runes and Latin mentioned above) into a place where they logically wouldn't exist.
Seriously, there are enough linguists here (and people like me--I minored in linguistics and play around with conlangs as a hobby) who I'm sure would love to put together at least a quick phonology and basic syntax for a language or two. It's worth doing.