So seems mostly I am the only one bothered with this, which is fine. It's a me thing.
Some of you brought up some interesting points that the empire incorperated several cultures into itself and so on. The Romans and Byzantine did so as well. However, even if some new names arrived into their alphabet (Weird wording, I know). their naming pattern didn't really change that much.
For example, there is a reason that we read about celtic people in more italic style names like Lucterius - who was a leader of a Celtic tribe under the revolt against Rome and Caesar. Also there were Armenian Kings/Emperors who also were written with Roman/Greek style of wording (Us/Os-endings) as another example.
By this logic, and from what we have seen from the Calradic Empire, this should also be mostly true as well. However, its not. And I don't think its because of logic of how things works. But more of a "this sounds good, cool and mostly right, let's go with that"
Thats my argument