Deutschland NT player Sezen Uygarli is actually Turkish like Mesut Özil :)
in germany there are a lot people with turkish origins who are born and raised in germany and also feel like a german, or like Mesut and Nuri Sahin like someone with two citizenships.
I would rather solve this by x% of German players getting names from Turkish name database and not incorporating Turksih names into German name database. Because no databse stands alone and most of them feeds at least 1% to other countries.
No matter how they are German citizens as everybody else, their names are not widespread in other countries the same as genuine German names are so it kind of spoils the purpose of having foreign feeds to get names traditionally spread in a counrty to some extent (BB doesn't allow feeds smaller than 1%) when you can get virtually anything from that feed including very random names who are not really represented in the feed receiving copuntry (and if they do it is a random event not a considerable population of that origin - while you can get much more of them by the feed).
It is not about German and Turkish names, I used it as an example. But I remember when I finished editing of czech database and was checking names from draft, Austrian feed kept producing nonsense name combination.
Another problem is, that you can't have first name from one database and surname from another. Which is probably generally a good thing but surely they are cultural specific area for which the option would be uiseful (typically when the bearers of the name kind of asimilated getting local typical first names and only the surname suvived through generations).
All is better than it was, in early seasons there were a lot of spanish names for my country and randomly there was a strong czech enclave in Puerto Rico:)