I understand your questions and ask you first play the public demo before reaching to a final conclusion. The overwhelming support I'm having from the people around the web show me that I'm on the right track. The story will be developed more in this game than most hentai that go by "defeat the sexy demon lady in her castle". If this doesn't appeal to you, there is nothing I can do and I sincere hope you find your perfect game one day. Since the beginning I said that the game will be similar to Lust Grimm/Friend, but with far more temptation events that will result in a actual sex scene in game that will steal your HP and restore the succubus'. However the game will contain sex sounds for all succubus. And I also don't live in japan, which is way easier to contact a girl for voice there.
There will be no voice, as it is expected from a first game from a developer. However, the majority of players love succubus with HUGE breasts, just take a look at Lust Grimm, so we decided to show them more for marketing decision. There will be many body types in this game. Some points you raised that I wish to address: I ask for you to play the public demo, hopefully in July, and take the conclusion by yourself. I will also post this here in case he don't see it on the older threat.