The questions here are, will Take Two tone down their game, or release it unrated, and also, does the game retail industry behave the same way that the cinema industry does, or instead like the DVD retail industry?
If a movie receives an NC-17 rating from the MPAA, most national cinema chains will not carry it. The movie is destined to fail, regardless of it's quality. It will get zero advertising and if it screens at all, it will screen in independent cinemas.
We know, at least according to this story and past history, that major retail chains will not carry a game that is marked with an "AO" rating by the ESRB.
Now, would it be possible for Take Two to release Manhunt 2 without a rating? There is nothing forcing them to accept the rating. In fact, movies sometimes do not accept their NC-17 ratings, and release "unrated".
For example, the documentary "This Film is Not Yet Rated" was fated with an NC-17 rating, and released "unrated" theatrically. The director chose not to accept the MPAA's rating. (The movie is about how corrupt the MPAA is, just so you know.) In the movie business, "unrated" is as good as NC-17, at least in cinemas.
On the other hand, DVDs are released as "unrated" editions all the time. In fact, it's a big marketing tactic. "Unrated" movies are not necassarily any more violent or sexual than their rated counterparts. The unrated version is simply not the exact same film the MPAA screened. Take a movie, add a deleted scene into the feature presentation (even if it's about kittens eating ice cream), plop it on a DVD and bam, it's "unrated".
Big retailers (wal-mart, best buy, etc) all carry unrated DVDs. So, how do they treat an unrated game? Do they act like a cinema and screw it, or do they act like a retailer and sell it?
For the record, I'm not passing judgement on Take Two or Manhunt 2. I'm just posing the question of how Take Two is going to handle this. Personally, I think they should release it unrated. If they believe in the product, and think it is quality, they should let the world see it the way they want it seen, even if that view is absolutely for "adults only". If retail won't carry it unrated, they'll almost certainly buckle and change the game.