Unfortunately as of the series conclusion I can safely say Kyoto Holmes is a safe but unnecessary mystery/shoujo.
Worth noting, I have no knowledge of Japanese art history though, which might present some additional entertainment value as its a subject i haven't seen covered before.
Story 4/10
As the biggest draw, to me, was the mystery, the lack of an impressive plot was a sad detraction. The mysteries weren't boring, but the cardinal sin of not giving the viewers enough information to potentially solve the mystery themselves is a sore point. Even then the mysteries tend to lack significant consequence, which brings me to the worst part. There was only one issue that was especially offensive, the weak attempt at modernizing Moriarty that falls really flat as almost everything about him is nonsensical. The writing portrays him significant but also refuses to let our protagonist lose, leaving him as no real threat. At worst there is a "technical" victory that they try to hammer home by having holmes react especially heavily but it doesn't feel deserved and marks a real low point in the plot. Its the painfully classic case where the protagonist-antagonist relationship is really contrived. The other subplots are at least good for a binge watch though.
Art 7/10
The style was consistent, seems a little over saturated at times but otherwise nothing to complain about. The subject antiques and art are fairly detailed although there were some objects that weren't given much focus. Character designs and outfits were lacking beyond the main cast.
Sound 6/10
Unremarkable.
Character 5/10
the main pair are set up is at least somewhat uniquely, but the end result is a tired standardized shoujo relationship that adds very little to the rest of the story. Again its not particularly offensive but it didn't end up very entertaining either. The heroine is occasionally competent, starting off lacking but ending up with at least one (1) redeeming quality. If you like female characters who act as victims and don't do much beyond that you'll love her. In contrast is the Hero Holmes, who's a borderline superhero, having no real flaws beyond some contrived heartbreak story that is repeated early on then eventually ignored so as to not interfere with the shoujo aspects. there was also the terrible antagonist and, about 2-3 interesting side characters, the rest were forgettable.
enjoyment 5/10
a simple mystery isn't unenjoyable but the weak antagonist (and even though sherlock/moriarty isn't the most holy of pairs, this bad of a rendition is still insulting) and otherwise lacking characters are not encouraging to say the least. besides the mysteries themselves, the props and art do provide some entertainment value though.
Overall 5/10
Its not offensive at all, the art style is nice. The mysteries are intriguing even though the characters aren't. The use of holmes in the name does carry some expectations, and those expectations were most certainly not met, as such i personally cannot recommend watching.