I agree with a lot of what others have already said. For me personally I only follow this series for the characters. The storytelling and lore lost me when we reached BBS. The Mark of Mastery and Keyblade lore was the beginning of the end for the story but thankfully the characters are still charming enough to carry me through it.
As for the series as a whole my opinions have greatly changed from when I first joined this forum. Somethings I didn't like much in the past I've grown to appreciate and love, while other things I've loved or praised in the past I've gone back on and and am now looking at my old post saying "I actually praised this? It sucks." and most of that comes from KH3. One of the biggest complaints in KH3 is how Sora isn't driving the series anymore despite the game telling us he's needed. Ironically one of the few things Sora was driven to do in KH3 (revive Roxas) was taken by another character in a total offscreen arc that had little to do with Sora at all, and it's something I've grown to despise in a love/hate relationship. So even when it's an arc that involves him he's a bystander.
The big bad of KH3 isn't even a Sora villain. He's a Wayfinder Trio foe and if this was really a character driven series they would/should have been the ones to deal with Master Xehanort in the end. And that's the issue. Everyone talks about how bloated the cast is and characters not being relevant anymore but that same argument applies to Sora and Riku, the two main protagonist. Riku did absolutely nothing in KH3. What makes him so valuable anymore beyond being Sora's best friend?
And that leads into the Union X stuff. It just creates so many plotholes. Nearly every Organization member was a Keyblade wielder according to the new lore minus the old scientists. So why did they need Roxas? Why did they feel the need to make a failsafe like Xion? They had a 'prodigy' Like Marluxia right in front of them. The original Organization XIII was ruined by their backstabbing and politics over one another, but now with the new lore they just look hilariously incompetent. I can't wait for the cutscenes to explain why they never used them. Or why Marluxia had to die twice to get his memories back.
My biggest complaint is we keep digging into the past to buildup the series instead of just moving forward in the present with modern day threats and crisis. That's why Sora and friends don't feel like they are needed anymore. They keep fighting these old fossils that have been around before they were born and have no direct conflict with. First Master Xehanort and now the Master of Masters. I feel like that is so limiting for the characters involved. One of the reasons I like the Yozora stuff is at least it's present day content, at least for now.
I actually enjoyed Chi/Union X up until Ventus showed up with Marluxia and Larxene. Remaking old characters into new ones because Nomura has clearly gotten bored with the old KH universe and wants to tell a new story, but instead of using Final Fantasy characters as the vehicle to gain a audience he's using the KH characters. Subject X being one of the biggest offenders using a fan favorite like Lea/Axel to garner interest in a character who doesn't even have a identity yet.
While I'm on that subject, one thing I've changed my opinion on. I'm more leaning on Roxas and Xion, two characters I still love, taking more of small backseat role. Simply because of how I look at how Axel's been written since DDD and I don't want that for either of them. If the direction was different I'd love RAX to still be around with big roles but now I'm just terrified they'll be written in a way where I'm sick of them. Just show them eating ice cream and playing on the beach and I'm good.
Before I just write a massive essay I'll give the tldr version, no I do not like the current direction. But I still love the series. If I didn't I would have quit. hopefully the new saga is good now that Nomura is more interested in it.