Why is this not "Hydropolis"?
"Aqva" is Latin; "polis" is Greek. Sure, this is a fictional world with fictional origins, but I'm curious as to why we're constructing names from roots of two different source languages. Is this something that sounds better to Japanese players? I can understand the Latin+Latin "aquacivitas" being awkward, for Japanese and non-Japanese players alike, but the Greek+Greek "Hydropolis" rolls off the tongue deliciously.
Garlean names have a very Latin flavor, but off the top of my head I can't recall any examples of in game naming that mixes Latin and Greek like this (discounting "hoplomachus" as a Latin word borrowed from Greek).