I agree completely. While I only include anal where it makes sense (in a porny kind of way), I do want to give the player a choice. If someone is into anal, they shouldn't have to go through a bunch of other scenes to get to it unless the game has good reasons to make it otherwise (likewise, if someone isn't into anal, they shouldn't have to see any scenes with it). They also shouldn't be punished for pursuing it. I don't want this to be the kind of game where you have a choice between vaginal and anal, but the game punishes you for going the anal route. I've seen that happen too many times.
In my game, these things depend on the character. At least one of the girls in the game right now is going to refuse anal access until you achieve a specific goal (note: this isn't in the game yet, so don't bother looking), but it's not treated as some kind of standardized game mechanic that I put all the characters through.
Generally speaking, I try to avoid tropes, both in terms of story and gameplay. When I do use tropes, I try to spice them up and make them feel fresh. Far too many game designers, not just in adult games, follow tropes on pure reflex. That annoys the fuck out of me. Everything in a game should be there for a reason.
