Alright, finally finished Heian-Kyo and yeah, it was definitely just meh with atleast some decent points that don't make it a true trainwreck but it definitely has some major issues.
The Story was ultimately just there as it was more character driven primarily with Kintoki Sakata himself taking the reigns so the story was never gonna be the highlight as it's literally just "Holy Grail War but not then Shimousa" and there was really nothing else past that.
The characters are absolutely, positively mixed. Kintoki is the biggest one as he is the Main Hero of the entire Heian-Kyo and... it's definitely hit and miss, as much as I hate to say it. My biggest problem is that it the entire deal with Kintoki is basically similar to Musashi in Shimousa except in a different fashion... but it doesn't really work. Musashi ultimately finds her own path to get to "Zero" and become the swordsman of legend that her male counterpart is(Even if she dies in the process) meanwhile Kintoki wants to find his reason to fight as what he came across since the start of the Singularity... the problem is that it feels like he already had it or to better say, there's no real difference between Kintoki Sakata of Heian-Kyo and Kintoki Sakata of Chaldeas. I'm not expecting the man to be a monster or lacking empathy or anything but it feels real off that there's no character development or anything to show Kintoki is truly changing, what we see is what we get which isn't disappointing as he livens up the Singularity hardcore, it's just that there's nothing showing any true change.
...Which leads to Katou Danzou(Yeah, I know I went with Western Naming for Kintoki, bite me) who might as well win the award for the most useless Servant in ANYTHING in FGO. I have legit cannot remember the last time we had a Servant helper that didn't even manage anything but be an exposition dump and genuinely a bad one at that(As she just repeats what others have stated or the scene itself alluded to like the reader is retarded). It's fucking weird as Shimousa didn't have this problem at all and the only times any other writers did this was in the older Singularities or when an event happened that couldn't be easily shown in full onscreen. It doesn't help she exists just to get her ass kicked and make everyone else look better(Tsuna beating her ass, the various monsters kicking her ass, Shuten literally taking her arm without her noticing) which feels absolutely odd because we long since know that Servants are sometimes weaker than their real life selves... but that really shouldn't work for Tsuna of all people.
Everyone else was middling to non-existent. We finally see True Raikou in the flesh and... she's pretty much just there, which is extremely odd considering the game hyped up her Saber Form for years as being her definitive self from the Heian era and we see her Heian Era... and we barely get anything. Tsuna is honestly alright but they really do lay it a bit too thick on his connection to Ibaraki and her mom, Shuten is okay, Ibaraki is meh and Ibuki-Douji was genuinely a waste(And I have to agree with TvDopes in that she exists just to get her Servant self over with, it is something that Shuten outright states if Ibuki is summoned right, she would just be a taller and nicer Shuten... which is what we ended up getting). And hilariously, Taira literally got more out of her than she did in her Event(While her Event did touch on Yoshitsune's fucked up death, the Story actually touched upon their entire beat as Servants moreso than the Event did).
Ashiya Douman is a terrible villain... but that's the point and I think it fits him best. I've seen people complain that he isn't the genius he touted himself to be and all I can think of is:
That's the point.
Douman was never a genius of his craft(God Arjuna just wanted to hear what he wanted to hear, The Heroic Spirit Swordmasters was just him going along with Alternate Amakusa's whims as well as his own and even Olympus was just him putting a tracker on Europa) and was a pure hedonist so he absolutely would forget the most basic shit about being a Beast AND earning Ibuki's wrath by being so indulgent on himself. Of course, I can't blame people who wanted a bit more meat from Douman but that's how I always seen him.
In the end, Heian-Kyo isn't Septem bad or any of the earlier Singularities' bad but it definitely isn't even in the good territory. Kintoki actually does save it from being bad or awful because the dude is infectious and the last set of chapters kinda saved it.