Stick to your guns Take Two. Release the game as you intended it and take the AO. If the game is great (as an early NGamer review suggests with a score of 92%), then people will buy it and the mainstream will have to acknowledge that an AO game can be a success.

UPDATE: So apparently Sony, Nintendo, and Microsoft don't allow AO games on their consoles under any circumstance. So an AO rating actually bans content in a country that's supposed to have free speech. The companies have their own rights, and this decision falls within those rights. However, it's always disappointing as a consumer to have fewer options.