My favorite incest games are the ones that deal with corruption and power, and I would describe
incest done right (with respect to corruption/power) as
using incest as a means of portraying the escalation of corruption/power by the continuous removal of barriers or pushing of boundaries to obtain sex. While I'm not much a fan of the romantic-incest approach, I do find it appealing when it's used to enhance a relationship or someone's personality.
Also I see the genre as "convenient" in that you have potential sexual partners just a few doors down. I can definitely see why lazy people get into it, why it's so appealing to developers, and how it's saturated with generic "lazy" porn.
My favorite examples are:
Dark Silver' Big Brother which was one of the first F95zone games I experienced and a huge dive into the incest genre.
Three of the
JSK Studio Games, which grants you incest based on either rape, corruption, or love.
Cmacleod42's A Spell For All which uses incest as a late-game achievement after you've progressed the story and accumulated sufficient power/resources.
Westane's The Company which advances corruption of your mom and sis (and you) by advancing incest through the repeated dosage of drugs.
Gaweb Studio's Glassix which grants you more sexual options as you gain more power (a ton of grinding req. without the cheats...)
F.Lord's Dark Magic
Kompas Productions' Summertime Saga