I doubt it's that simple, but it does feel like a wasted opportunity.
Even if it were just optional.
I really don't know why you seem to think it's a wasted opportunity since incest WILL be present in the game (it already is). If the tag is missing, it's because they didn't put it.
Also, you can play both doctors or just one of them. If you play both you'll simply discover more paths, stories and events, but it's not mandatory at all!
There will be lots of gay romance options. However most options will be one-night-stands only, because both characters will be able to date only certain characters (else it would be impossible to finalize the game ever). But there will be many characters to choose from. The game is just a 0.0.8 ALPHA release, remember this.
The game will focus more on the psychological/dialogue side of medical exams. Forget all the trial-and-error from the first game, you won't need a degree in medicine to play this game. Some exams will be routine, others will be more challenging, but it's still doable for everyone. And medical jargon will be present too, for the fans of that.
Please support the game if you like it! The game really needs your support on Patreon/Steam, because it aims to be better and bigger than any of my previous games, so it's up to you to make it happen.
Thank you for all your feedback, it will help me a lot in developing this game.