And a lot of "european or american state in the world" speak Russian or German?

English is certainly an international language, but after that, I'd say it's probably something like Spanish, which is close enough to Portuguese for being able to speak both relatively easily(thou might cause confusing word crosses if you do). That would cover most of Latin America, a large chunk of US population, a couple country in EU and actually a few countries in Asia.

As far as the community that play this game goes, the next up is probably Japanese because..... reasons.

And I would guess Chinese after that. For one, it's not nearly as isolated as you think. There are actually lots of speakers in Europe and America. For another, there is the HK servers. And finally, don't be surprised if some people with advanced experience from CN servers came here so they can tramp on noobs who have no idea what they are doing.

German and Russian? I doubt those language rank very high by not only population, but region or country where it's used in any extensive manner.

And finally, I know you don't have any idea how AI works, have fun designing *l encompassing behavior tree that is feasible to implement yet near optimal at all times. I also know that you lack knowledge of player power distribution with your power bracket idea. And intentionally or not, you are throwing certain players under the bus, as any "simple" scheme would. A truly fair scheme... well.. it gets complicated.

If you really want to prose as intellectually superior, some research and modeling would be really helpful. To have a plan that at least in theory more or less cover all the details. Make sure to check under the bus!