I'm still enjoying the series, but I will admit that a large part of this enjoyment comes from anticipation for the future. For example, I've been expecting the KotA to end up serving under King Arthur since chapter 1 and we're only now just getting to that point after 5 years of serialization. When Nakaba first brought up the sequel early into NnT he described it as a story about Arthur, which along with the fact that the Knights of the Round Table are perhaps the most important aspect of the Arthurian legends essentially means that we haven't even gotten to the meat of the story yet. It's something to be excited about, but it also highlights one of the major issues, that being the pacing. Nakaba is taking things very leisurely and it manifests in some things taking much longer than you'd expect them to. The tournament arc lasting for over 50 chapters is the biggest offender here. There were certainly important developments happening in that arc, such as the return of the other main characters, Percival Platoon getting their STs, the debuts of Gareth and Balin, Beltreipe's proper introduction and Diodra finally becoming more relevant, but was this enough to justify the story spending an entire year in the same location going through a predictable tournament bracket?
However, even the pacing pales in comparison to some of the writing decisions. The villains not feeling like much of a threat is probably the most discussed example of this and it definitely is a problem. I can sort of understand this approach when it comes to the Sins since they are supposed to be these legends that have to live up to their hype, partly because it means it's a big deal when the KotA eventually surpass their predecessors, but this doesn't excuse even the youngsters having a fairly easy time with the antagonists. Lancelot is of course the biggest offender here given that the power discrepancy between him and the enemies is so large that Nakaba has to constantly keep distracting him with something or just write him out of the story entirely, hence why he was absent from it for like 70 chapters. This is what happens when you include an Escanor-style powerhouse to the main cast without giving him a proper weakness to balance out his strength. Achilles had his famous heel for a reason, because otherwise his story would have been less interesting to everyone except for the Ancient Greek equivalent of mindless powerscalers obsessed with aura farming over the actually important stuff. That said, it does seem like this issue is going to be addressed sometime soon with how Lancelot is set to receive an ST that would otherwise make him even more broken. Nakaba understood that Ban had to lose his immortality after the Purgatory boost to prevent him from becoming completely overpowered, and we're basically just looking at the same situation again. Things should be fine as long as Nakaba doesn't somehow manage to unlearn his previous lessons.
Aside from the villains there's also another issue that seems to bother me more so than many other readers, which is how some plot points are resolved in very odd ways or sometimes seemingly abandoned entirely. A good example would be the Drug of Yore that was the objective of Worreldane's assault on the Fairy Realm. You'd think her success on this mission would amount to something important later down the line, but no, she just used the Drug to create some fodder enemy that was defeated largely off-screen by side characters. Great. The Perils themselves also fall victim to this with how Cath spent almost two decades to build them up into a force to counter the Sins, only for them to accomplish... what exactly? A handful of panels of them fighting their designated enemy until Ban just casually one-shots the entire group, after which Cath robs them of their powers. 18 years of effort for a few minutes of payoff? This is like the reverse of having a child by accident, which is a few minutes of fun resulting in 18 years of work. Jokes aside, the thing that bothers me the most here is that there was plenty of setup for the KotA to eventually defeat the Perils, especially when it comes to Percival and Ironside finally concluding their entire series-long feud, only for this plotline to be seemingly abandoned without a proper conclusion. There is still some hope that the Perils could be brought back since Cath himself is not done yet, but right now things aren't looking great on that front.
In conclusion, even though my overall opinion regarding the series remains positive and I'm quite excited for its future, there are certain elements that I believe Nakaba has handled poorly and that take away from my enjoyment. As for how things could be improved, some of these problems would be pretty easy to fix and Nakaba has previously managed to do it just fine. I already mentioned the issue of how to address overpowered heroes in the context of Lancelot, Ban and Escanor, but the other side of the equation isn't a particularly difficult one to balance either. In NnT there was essentially the opposite problem in the sense that the second set of major villains, those being the Ten Commandments, started out way too strong to the point that they made a good 95% of the cast totally irrelevant in the context of fights going forward. Forget about important side characters like Gil and Howzer getting a chance to shine again, because even main characters like King and Diane couldn't put a scratch on the TC until much later. Making the villains overpowered comes with its own set of issues so I don't want a repeat of that with what comes after Cath and the Perils. Rather, I'm hoping that Nakaba can find a nice middle ground after first going too far and then not quite far enough. The pacing is the one thing that might not really improve since it seems like an intentional decision. Nakaba has always wanted to write a story about King Arthur and was already utilizing Arthurian elements in his works almost 30 years ago, so this series is essentially like his dream project that he's been preparing to make for most of his life. I can understand why he'd want to turn it into a proper epic that goes on for years and years both in and out of universe, and there is a case to be made that a slow burn is preferable to rushing even if the former might sometimes be a little frustrating to sit through while reading the series week-to-week. Bleach was my introduction to the world of manga so I'm well-acquainted with chapters in which nothing happens.
Also, the story being split into parts is not something unofficial. At the end of chapter 128 there is a little note that announces it as the end of part 1 so this is coming from Nakaba himself.
Also, better logic and or at least clear explanations regarding certain things? This fight happening in Liones with civilians being there and nothing like Teleportation Incantation Orbs. They could have even asked Gawain to wait just a few minutes and teleport them? Forced developments for this dumb fight.
I don't think the civilians were really an issue. It takes a lot of effort to teleport that many people, as seen from the fact that Thetis collapsed from exhaustion after transporting them to Liones using the amulets. Her and Gawain were the only mages available to the Sins and you wouldn't want Gawain going into the Camelot mission already tired from the get-go. Incantation Orbs can't be used to teleport large crowds due to their small area of effect, seemingly only a couple of meters judging by Sin whisking Percival and Donny away right in front of Pellegarde. This left Merlin as the only person who could have potentially saved the civilians, and her power seems to be very limited in her doll form judging by how helpless she was against Cath. There wasn't much the Sins could have done better.