From MOBA point of view:
LoL being the easiest of top 3 MOBA leagues, the least complex (except item wise, which is the most complex), and the fanciest graphics. 32 million strong fans, mostly US and Western Europe.
DoTA2 being the hardest, the most complex, and the stay true to the original graphic, 8 million strong fans, spread across the globe (Asians and Eastern Europeans).
HoN, being the average, but with the worst community (l33t only, n00bs will commit suicide) mostly Latin Americans.
However, since USA is all about culture and counter-culture, we will see that the predominant community facing loud and very opinionated minority like VonMudra.
I can't say the same for Flight Sim though. The Europeans are big on figures and systems, while the Americans stress on the "feel" and the "looks." When they went all-out on creating the most realistic aircraft representation ever on PC: Europeans failed, the Americans succeed (Airsimmer vs PMDG). The Europeans simply forgot one thing: engine limitations on figures and systems. While the Americans overcome it by writing numerous stand-alone modules and requiring more processing powers.