This is a forum for linguistics, which is the scientific study of language, not about language learning or proofreading. There are many English learning or English usage forums on the internet. In this case, maybe your best feedback would just come from asking (potential) players, on a gaming forum.
As for the question, I don't think it matters so much because players will get used to the names, which will have specific meanings in the game anyway.
As for a little semantic analysis, the words you have picked do seem a little odd to me with "quality" in the middle. Try listing them out to think about semantic sets of properties. You have old/modern, and rare/common as clear pairs of semantic sets, but the medium category doesn't fit. This isn't really a question of translation, but meaning. Once you know the right meaning you can find the right word. But again, a gaming forum is probably the better place for this discussion.
