As I said before, I agree with you that he should improve his communication with the community and be more honest about progress. But again i wouldn't rant that much above promises made, you can play his game for free and the support is on a voluntary basis as far i could see there is no content behind paywalls. If you are not satisfied by his work just don't support him.
Actually, in the first post, there's a warning saying that the developer does not condone sharing the Patreon exclusive content, which includes the game itself (the game is uploaded by F95zone upload team). Therefore, it can be said that the game is actually intended to be "behind a paywall" (Patreon), and the only reason why we can play it for free is because F95zone will share it regardless of Dekarous' complaining about it.
Also, in the spoiler under the Overview section, you will find this:
1.0 includes the first world, the Realm of Dusk, completed. Every update after this will include the next world and its new Domina.
DISCLAIMER: 1.0 and its bugfixes are free, the next updates will be patron only.
So, the only truly free release is 1.0, which features Katrina's realm. All other releases are not intended to be free.
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I do agree that gamedev is often underestimated. Even RPG Maker games are not exactly easy to be done (especially if we are talking about good games). It is a multidisciplinary work, which involves programming, artistic work, storytelling and so on. When you put lot of simple things together, it becomes a complex work.
However, people are not wrong when they complain about Dekarous, as there are a lot of gamebreaking glitches from past releases that are still in the game (I think that glitch that happens when you enter a wrong door in Franziska and breaks the game still happens).
And well, that ~45 days per release is still in his Patreon, the last release was about 8 months ago and the next one is not even supposed to bring the next Domina. He should at least remove that sentence from his Patreon, as it was far from accurate in the last 3 years.
And Shakie's workload isn't as big as Deka makes it out to be. He actually commissions her for the strict minimum (Like 3-4 CGs per chapter + dialogue images). She's far from overworked.
I agree that Dekarous is (probably) the most responsible of Domina's delays, but the only reason I don't completely agree with you about Shakie is because I don't know if she is working in other projects besides Domina. If she does, that would be a valid reason for her to be overloaded (2D arts are somewhat hard to make, there's a reason why most games uses Daz renders or Illusion assets; if Domina is not her only commitment, it could give us a another reason for "why so much delays?").
Since the probability of Dekarous pushing his lack of commitment in the artist's behalf is far above from zero, I simply can't say a thing about Shakie's part in the release's delay. There's just not enough information for it.