Glad to hear that you're enjoying the server! But as stated above by Awcken and FeaturingAnxiety, I don't think adding more ranks/ cosmetics would be a good idea.
Personally, I think adding purchasable tags to Olympus, and adding a few more for the other servers would be a nice idea, since it wouldn't technically affect anything in-game, but would give players more freedom when customising their nicknames/IGN's.