Yea, as far as voices are concerned my view is as follows.
Voices do definitively add to a game. Like, they do. No questions about it. A properly voiced game, and by that I mean voiced in ALL the dialogue and not just the sex scenes definitively stands out above others that are not. It adds a whole new layer of immersion to the whole experiance that you just don't get otherwise.
However, I do not think that voice acting is worth implementing at this stage of development just yet for a number of reasons.
1. Adding voices to just the sex scenes and not the dialogue is weird and I wouldn't do it. It's really an all or nothing deal. Same goes for only voicing some but not all characters or any other shortcut. It's an all or nothing deal. And that means it's a big cost in both money and time.
2. Finding voice actors is hard. Finding GOOD voice actors is harder. And even if you do they don't come cheap and you have to constantly be tied to their schedule and rates. None of which is conducive to your work schedule being smooth. A number of games I am following online have the issue of being constantly delayed because this or that voice actor couldn't show up or couldn't be found.
3. You have to lock down your dialogue. If every change requires rerecording the whole scene over again that is going to add up really quickly and slow things down to a grind. And the dev here loves to go back and fix old scenes.
So honestly, whilst I would not at all be opposed to adding voice acting to this game and indeed think it would contribute a lot to the experience I think it's something that should probably be done at the tail end of development when everything has been pretty much nailed down and you don't expect any major rewrites.
Properly voiced games are good, yes, but then there's the issue of access to voice options and the money invoolved, a problem that is unique to small developers. To be properly voiced, there are multiple criteria.
A. The voice has to match as closely as possible to the face. This is a major issue in the dubs of anime because it is rare that this happens.
B. ALL lines have to be voiced. The Neptunia games run into this frequently where either one or both languages lack the voiced lines, usually English, less often Japanese, and always because meeting this criteria would overshoot the budget. You mentioned this in point #1 and I agree, if not ALL lines are voiced, it doesn't add to the game, now it detracts because it makes the game look unfinished.
C. The code has to be implemented properly to allow ONLY the voices to be lowered as needed. As someone here said, I may just be getting blind here, Ravager has this issue. Under absolutely no circumstances should the player have to lower their system sound to lower the specific sound they want to lower and under absolutely no circumstances should a player have to sacrifice, for example, the music volume to lower the voices.
D. Each character MUST be voiced either using the same person with a different voice being delivered by said person or using different people entirely. As you said in point #2, that can be extremely difficult, especially for small developers. This also makes adding voices detract from the game instead of add to it if the same person is voicing multiple or even every character and doesn't know how to change their voice to be as different as possible.
Responding to your remaining points not covered above:
3. Absolutely, one of the biggest mistakes you can make with voice implementation is to put yourself in a situation where you have to pay the person multiple times because you need to rehire them for a future session after having done one already. This can lead to a Neptunia situation, where not all lines get voiced because there isn't enough money in the budget to fund further voice work.
I am also not entirely opposed to the idea, but it has to be done right or not at all and, if it isn't done right, I will oppose it. Furthermore, sex sounds I DO completely oppose because, in my experience, they always sound like generic, prerecorded garbage from some open source library. This goes against criteria D as the developer has no control over who is voicing the character during sex scenes.
I want to add a disclaimer here, "Quality voice acting can add value to a game, in limited ways." But that is far from a guarantee, as good voice acting is hard to come by, especially in the adult industry, and if you don't like the voice acting, it really takes away from it.
Worse when it is the MC and the voice doesn't fit your concept or play style.
Definitely far from guaranteed, especially with a large and varied player base that may be majority against for all a developer knows. It is a major gamble with the life of the game on the line. The worst part is small developers don't really have quality to choose from. With quality comes increased cost, exponentially increased cost. Some of the big names can charge almost Hollywood level fees for their presence and there's no way small developers can take that big a risk, paying a huge amount potentially just to get backlash from the majority of players.
I would prefer larger updates without voices rather than smaller content updates with voices. I generally tend to mute all sound.
I don't mute, but I'm with you on the content amount. I like that we get as much as we do with Harem Hotel, but we won't continue getting that if voices are added, at least not for a while as Runey adds the code and coordinates with voices.