I think I'm the only person that likes the direction. However, I think the execution is the problem.
When I look at the entire KH story, I take a gigantic step back and see so many interesting ideas, themes, and plot points. The problem here is that because all of these things were introduced so haphazardly across a variety of games that spanned a variety of characters/time periods, it's hard to really enjoy these things unless you really take the time to understand and appreciate. Back when BbS and Days came out, they both felt like stories that just added on to the lore of KH: Terra became Terra-Xehanort, there was an explanation for why Maleficent started looking for the 7 princesses of heart, Castle Oblivion's origin is explained, we could assume why Roxas looked the way he did/could dual wield etc. Nothing from those games really spelled out "we're building to KH3" except oddly enough coded. So even after playing BbS and Days, it just felt like there was no direction and we were just getting side stories to enhance the lore.
Then 3D came out and blew everything up. I feel like 3D is where Nomura truly dropped the ball. After all of these years and side games, if he really wanted to steer the series towards a certain version of KH3 (one that would be ostensibly better plot-wise and a better payoff), then 3D HAD to be the game to do it. I think that if 3D was a longer game that was on PS3 and the sole focus was to build to KH3, that would have served KH3 a lot better. I actually feel like 3D should have been like CoM, where after you beat the story with Sora/Riku, you get the Aqua story in the Realm of Darkness. That way you can touch on all the characters and past stories that were kind of stagnant.
If I were to frame 3D, it would have been that Mickey insists after coded that Sora and Riku do their Mark of Mastery because he discovers Lea or one of the other Nobodies have been recompleted. This will remind him of when he met Aqua and she tells him about her fight with Terra-Xehanort. Mickey immediately informs Sora and Riku that the reason for the urgency is that he realizes that if a heartless and nobody are destroyed, they get recompleted which means Master Xehanort has returned. The story could be rewritten that while Sora and Riku do their Mark of Mastery in the dream worlds, Mickey goes with Donald and Goofy into the Realm of Darkness to save Aqua - as he suspects that she will be Master Xehanort's first target (because Mickey knows Xehanort will want to find Ven). I would continue writing the fanfic, but it's late and I'm tired - but basically, some of the things that got time wasted on in KH3 would be dealt with in 3D. As epic as it was to see Aqua get saved in KH3... the pacing is just really bad in the plot. Saving Aqua was contingent on Sora getting the Power of Waking, which meant that it had to be shoved to the end of the adventure - along with everything else.
Anyway, my point is that 3D is where Nomura could have really course-corrected the series. There was no game that really lead us to KH3. It's just fragments across several games that are not really tied together. If Nomura really was going to use Days and BbS to build up to KH3, he should have emphasized the Replica program in Days (like just how important it was to Xemnas and/or maybe even reveal the Organization's true purpose in that game) and he should have Master Xehanort explain time travel and/or the contingencies he had planned in BbS (or at least hint to them).
With all of that said, I think KH3/ReMIND did a really good job refocusing the story onto Sora, making use of the DISNEY worlds, and writing off story elements that Nomura probably isn't going to really focus on going forward. OK, the last part he didn't do a "really good job on", but I think he did the best he could considering that he lost a good chunk of development time on KH3 and that he wrote himself into a corner with so many characters (which he himself admitted). As sad as I am to see Nobodies probably get written off, it's probably best to get rid of them now. They were a plot device for Master Xehanort and all the key nobodies have been recompleted.
As much as people don't like this direction of KH4, I think Nomura actually did the best he could to course-correct the franchise. He learned from the mess that he made for himself with KH3 - there were WAY too many characters. So now he refocused the story onto Sora and essentially locked Sora away from all of the old characters, so Sora can start fresh with new characters. That should make it easier for Nomura to write Sora and KH4's story. The question here is whether this is the right decision. A lot of fans will be upset that their favourites will probably not be in KH4 (I pray for Roxas and Xion to cameo at least). The best we will get is probably Riku, Kairi, Mickey, Donald, and Goofy.
Ultimately, I think it is good to start fresh and trim off characters and plot elements from more than a decade ago that Nomura is clearly not interested in anymore. I like to believe that Nomura learned from the Dark Seeker Saga. Not only did he learn, but I think he's seeing that it's a new era of gaming. There are no "handheld games" to be made anymore. It's basically full length console games with DLC or mobile games designed to make money. It is sad to a degree, honestly. I say that because Nomura actually did something that most other franchises did NOT do back then - he actually made every single entry in the franchise connected and relevant. Other franchises could have a game come out on GBA or DS and it would probably not be connected to the main console titles. Nomura actually did something creative and special in a unique era of gaming, something that we will probably never see again. The fact that he was gutsy enough to do that, honestly, makes me give him a pass on what became of the franchise.