To be honest, I feel that this is kind of fair. Also, this is old news.
Anyway, there aren't a lot of MA15+ games that don't warrant R18+. The only exceptions I can think of are 'Half-Life', 'Team Fortress 2', 'Second Sight', 'Call of Duty 4', 'Painkiller', 'Serious Sam', 'Silent Hill 2', yada yada. This might sound like a lot of games, but take a look around and you'll find a lot more than just that.
To be honest, that's a heavy sacrifice, but I think it might be worth it. Game developers may actually calm down for once and focus their games on things that aren't swearing, blood and breasts. Hell, 'inFAMOUS' was rated M. The 'Portal' series is PG (at least, it is here in Australia). 'Prince of Persia: The Sands of Time' was also rated M. What do all of these games have in common? They are the top dogs of their time and still remain standing to this day. In contrast, I barely remember most MA15+ games that I play. Hell, 'Halo''s only an M-rated game and it's one of the most popular things ever.
There's nothing stopping 'Vanquish' from being an M-rated game except for all the swearing. This can apply to a lot of games, but maybe this will encourage developers to be more sensible for once.