The issue I see here is that the Elder Kings team want to make a fully current-version compatible, relatively bug free and feature-filled update for their next release, but circumstances make fulfilling all of those at the same time impossible: if they get a bunch of new features ready for the current version of CK2 there's gonna be bugs, if they keep the features and clean the bugs a new CK2 update means they have to scramble to update and then fix everything while being distracted with the possibilities added by CK2 patches in regards to new modding opportunities, and if they release a bug-free version for the most recent update then they'll have to prune features. Without a larger team and a wider pool of testers it's difficult to make a perfect release that hits all three marks while being playable for more than a few days before a new CK2 patch drops and the cycle starts all over again.
Right now dedicated fans will of course install the SVN version and play it, dealing with the bugs and daily updates wrecking their saves while enjoying and testing the release, but it's a hurdle for less dedicated fans who aren't going to deal with jumping through hoops to play an unfamiliar mod when they can play vanilla or a regularly updated (and admittedly more famous, if only because of the pre-existing fandom) mod like AGOT. This is okay for the devs who are focused on perfecting their mod and the testers willing to deal with the issues the SVN version comes with, but it's making a rift within the community between Elder Kings fans willing to play and enjoy the SVN version with all its faults and those who don't want to waste time on an incomplete mod. "Casual" fans just want to have fun with the mod rather than spending their limited free time on setting it up and dealing with the issues an in-development build comes packaged with and "hardcore" fans dislike the insinuation that Elder Kings is a failed or abandoned mod because it hasn't had a full release since 2016 and that those playing the SVN version are wasting their time.
Neither side is wrong, really. Most players don't have the time or patience to patch the mod every day and restart their games every day, nor do they want to install extra software on their computer to play a mod in a game they have already installed software for. This is an absolutely fine viewpoint to have, and accusing them of laziness in not installing the SVN or impatience in wanting a full non-SVN update sooner rather than later is not doing anyone or anything any favors, Elder Kings and its devs in particular. Similarly, those players willing to deal with the issues of the SVN version in order to enjoy the mod or help test it for a future release are also in the right, and accusing them of elitism isn't helping the situation either. The more accusations get thrown around the more heated and divided the community will get, and the last thing Tamriel needs is more beings on another plane of existence from Nirn arguing over it.
As for me personally, the SVN version is no particular hurdle to me and I'm more than happy to play it, but I do think not having a major update in so long is dangerous for Elder Kings as a mod in development. The longer the wait the more casual players will lose interest, and there's probably at least one gamer out there who has ceased playing CK2 altogether while awaiting an update and thus will never be able to enjoy the mod. A shrinking fanbase means less incentive for the developers to continue work. I still recall Dawn of Victory, a mod for Sins of a Solar Empire which was determined to only make perfect, bug-free releases, and after years and years of work the development team lost interest and fell apart, and the mod was abandoned without ever seeing the light of day. Elder Kings has already had releases before, of course, but I would still prefer not to see Elder Kings lingering in development hell or abandoned by the time we're all playing CK3VR or floating about as piles of radioactive ash or something.
That being said, I'm not a part of Elder Kings' development team and the above is just my personal opinion on the situation. I can see both sides, and as a whole I'm not on either of them. Or maybe I'm on both at the same time. Mundus is kind of odd that way.