The actual execution was a mess, but Skullface's inspiration for his parasite weapon being the experience of linguistic imperialism as a child was a really novel premise. The idea that he would get his revenge by creating a weapon that killed anyone who spoke English is some cool super-villain shit I don't think I've ever encountered before. "Race-selective" weapons, genetic-targetting weapons, religious indoctrination viruses, I've seen all those, but I think MGSV is the only time I've encountered a weapon that targets a language community.
My problem with it is that it (and like other things, like the prime directive from star trek and ect.) just kinda reads like someone just found out that white people did a lot of evil. I'm at work atm, so I don't have time to go into it with details right now.