Why the Byzantines didn't already had their architecture style changed before?

As you can see in the AoE2 Definitive Edition preview, the Byzantines now have the Mediterranean set (the same that Italian and Portuguese use currently; Spanish are also going to have this set) instead of the Middle Eastern one.

This is a very good change. It was always so incredibly weird that the Byzantines would look like muslims and their temples would look like mosques, despite the fact that real life Byzantines were christians (and their architecture looks nothing like Islamic architecture).

However, something that I don't understand is why they didn't already changed this before. This is because the Mediterranean set was already there ever since The Forgotten was released. They could just have changed this back then.

The only possible explanations I can think of are, is that they couldn't change it due to two reasons: Either because it was hardcoded in the original game (they couldn't change anything in the original game for some due to technical limitations) or because of copyright issues (they couldn't change anything in the original game because they were prohibited) - Otherwise I can't think of any good explanation.

As a side note, I hope they also take the opportunity to change Vietnamese to East Asian instead of Southeast Asian, and possibly Huns to either Mediterranean (to match with Romans/Byzantines) or to East European.