Let's say the player can decide one area to be more sensitive than the others, like in DoL. Let's say the boobs for example. If the player makes this decision, he wants to see more boob content. Now in combat though, he has to keep the enemy away from the boobs, because he takes more damage if they touch him there.
I generally feel like there is this misalignment between what the player wants to see and what he "should do" in combat.
Of course he could sabotage the combat and not play the game to see the stuff he wants to see. But that's not a good game.
The problem is that it shouldn't have influence on you but on the enemy moves, let's say that you are making a battle-fuck game, here is an enemy template:
-Tiny Succubus girl with big boobs with the following moves:
*Breast smother
*Boobjob
*Footjob
We can see that she would be a girl that favors a boob fetish but that also has a move for foot fetish, she would be a NPC that at the start would focus on her main appeal, boob moves, but if they aren't very effective she may notice that the character has a foot fetish and decide to work on that. Basically 3 situations
-MC has a boob fetish -> Succubus focus on her boob moves
-MC doesn't have a boob fetish but has a foot fetish -> Succubus will notice it after a few turns and focus on said moves.
-MC doesn't have a fetish that fall under the moves of said character -> Succubus focus on her main style which in this case are boob moves.
A game that kinda has a system like this is monster girl dreams, in which a few characters will notice your fetish values and focus mostly on your weakness, however just because it is a weakness shouldn't mean too much, like for example give fetish levels and related to it you receive more damage from said moves.