What do you guys think of something like chemistry, there are teams out there with 11 different nationalities in there starting 11. But how can they communicate? If you include something like chemistry you can play with home-grown players more which makes the game a little bit more realistic in my opinion

I think this would be really hard to implement. For example, should only nationality and language count, or does culture also affect chemistry? Players from South-America usually have no trouble settling in Spain or Italy, there are lots of African players in France, players from the Caribbean usually settle well in countries where people speak good english. Then you have clubs like Fulham, Chelsea, Arsenal (maybe not so much anymore tho), Man City who have lots of nationalities and still make it work.

It sounds like a cool idea, but it will demand a lot of effort to work if you want it to be realistic.

Yeah you have a good point there. But what most managers do including me, I search for players in the most random countries with the worst NT team so the player will be in the NT faster and get more EXP. But that is a bit unrealistic i thought.

But with the Chemistry i thought maybe you can make something like Fifa ultimate team or something.

I do that too, creating players from small nations doesn't have any negative consequences in the long run. In a few seasons almost every national team will have a decent XI, making what you mention a temporary problem that eventually solves itself.