Arguably, the incest fetish games kind of became "the thing" and themselves became pretty generic. Summertime Saga is one that wasn't/isn't all that generic, by virtue of it actually being a good game/VN.
I'm not a big incest fetishist, I'm drawn more to the overall quality of content & story, but I personally find that when a game that has incest as part of the story, (especially when it's blatantly obvious that it was meant to be) I pretty much fall on the side of the "pro-incest" argument in regards to artistic/authorial integrity.
When it's just in the game to capitalise on the popularity of the fetish, the game itself usually turns out to be pretty mediocre, i.e. Big Brother. Not a good game, horrible story and mostly horrible characters (especially the protagonist) and is propped up solely by the incest and the renders.