Honestly, the only place I know that actively try to discourage people from using Kplug is that one Koikatsu Discord server, in which they auto-ban anyone who mentions using it because they feel threatened by it or something; and yes, they will say that you threatened an admin if you disagree with their opinions regarding Kplug, but that beside the point of the discussion -- as the majority of the people from F95, Reddit, Steam, Illusion Soft, 4Chan, and other private Discord servers seem to weigh positively in favor of using it.
And while I'm certainly well aware that Kplug can lead to incompatibility with the rest of the mods and ruins the gameplay experience if it wasn't installed correctly, if it reaches the point where you have people willingly uninstall incompatible mods just so they could get Kplug working, that kind spell that those other mods just aren't as important as having Kplug running in the game; and that ultimately should be general consensus. But alas here lies the problem:
1. The people who produce these mods do not play the main game. (Yes language update is good, but they're texts not features)
2. The most vocal minorities are the one who play Character Studio and not the main game / H-gameplay.
The second point being the most obvious as if you were to ask anyone who play Character Studio how to properly install Kplug, they'll just tell you to avoid using it, but really offer no alternative solution in place; which is really a dumb logic to be honest, "Don't use X because it's bad, but X is the only way to get it." or "Kplug is bad, but that's the only way you can invite multiple characters", or recently, "Kplug is bad, but we use their animations for our Animation Loader."
In whatever case, Kplug does stand as a worthy plugin in its own right, and if you're the kind of person that get off on the main game and H-gameplay I would strongly recommend giving it a try because it does improve the gameplay significantly with a lot of features added; and yes there is a public-released version that you can download for free.
It has been semi-actively discouraged at times by the maker of both the HF patch and Better Repack as well, particularly around the time they tried to get Katarsys to switch literal months of work from the IPA framework to BepInEx. However, nothing on the level of auto-bans unless you count the mysterious disappearances of comments JMccovery mentioned, that seems like overkill to me on both the Discord and here.
It does have occasional issues, true, but they aren't bad enough to warrant dropping the mod and Katarsys does address them and fix them when they are on Kplug's end and he is able to do so. Any compatibility on the other side is, of course, not within his power to fix.
1. Genreally speaking, most people are into Illusion games for the studio aspect, at least as far back as these studio programs go. This wasn't always the case, but it really started to become prevalent once Illusion started dropping the ball in the actual game. Also, Kplug has no studio functionality, it's all in the game side, so they don't see the need for it because they lack, either totally or largely, the game playing aspect in their usage.
2. Likely true because of what I said in 1.
They tell you to avoid using it without an alternative because no alternative exists. To their credit, they would give an alternative if they had one. There's a mod for the positions, but ONLY some positions and ONLY the positions aspect of Kplug. Only once the entire Kplug mod has an alternative will there be an alternative. That means everything I listed before has to be implemented and it has to be at least equal in quality to Kplug. If all of it does get implemented, but it is not as good, it still doesn't replace Kplug.
Beware of venturing down this road again, lest more posts mysteriously disappear.
If it gets asked about or a misconception is made, the question gets answered and the misconception corrected before it can become too widespread to fix, like the msiconception about this website being for porn games specifically when it is not already has. The misconception in this case was that Kplug only adds positions, a misconception implied by the comment I replied to by stating that Kplug would not be necessary in RX10. While, technically, no mod is actually necessary in any build and this has been true since before Better Repack existed, Kplug is still considered necessary because it does add much more than positions.
As for mysteriously disappearing comments, that should not be happening, we are on topic since there is literally nothing to talk about for the game itself, only mods, which Kplug is one of, and no other rules are being violated unless someone starts getting rude. If a moderator is deleting posts about Kplug, a mod for the game this thread is about, without any rule violation, they are doing too much deleting. If they are going to do that, they should just lock the thread entirely since even that is off topic or rule breaking and, because it is a mod for the very game this thread is about, no other mod should be allowed into discussion. All that said, I don't want to see any of the above happen.
Any word on what Sunshine is/when it will be released?
Koikatsu sunshine release on May 28.
Have they said if it will share the same compatibility with Koikatsu that AI Shoujo and Honey Select 2 do? I'm actually very interested in that possibility because it is implied by the fact that it is using exactly the same art style as Koikatsu, but implication doesn't mean anything in game development until they actually do it and, even if they do, it could be the same as AI Shoujo and Honey Select 2, different voices and personalities on the same character. I hope they actually do it with the same voices and personalities as Koikatsu since that prevented me from using my AI Shoujo characters in Honey Select 2 because it's just too jarring a difference when the same character has a different voice and personality between games.