>It's clearly branched out further than just about Shirou's story arc, though.
The only thing that branched was the lore, because Nasu is a very established lore whore—hence him releasing four different almanacs with background stories and snippits on characters that may or may not have had any screentime. Granted, actual story did result at least one time with Fate/Zero. The rest (Tiger Collisseum, Extra, Extella, Apocrphya, FGO, etc) are either silly spin offs, waifu spin offs, or substanceless dreck built entirely on the premise of "Who's that historical Pokémon?!".
>And taken by itself, his arc is your typical shounen tale out of Japan.
Debatable. Especially since so much of the narrative goes out of its way to show you why Shirou's distorted optimism, often a staple in many Japanese stories, is such an unhealthy thing, despite others (Rin, Sakura, Saber, and even Rider) wanting to believe in it.
That's a side peeve—people often labeling it shounen demographic when they really mean naive hero obtaining godly power to punch demons in the face with panyshots in the background and nobody dies...and that actually doesn't describe FSN very well. But, again, side peeve of no consequence.
> And Nasu also clearly wanted the Fate 'universe' to stand on its own considering how much sheer dialogue in FSN is devoted to explaining the HGW, servants, myths, and the mechanics therein.
Already covered, but Nasu's a lore whore. He wrote just as much (if not more) on the frame setting that became Tsukihime (and Kara no Kyoukai before that), and has, iirc, done at least four scenarios on the End of Times (1 featured in Extella, another 2 being the carrots you chase in FGO iirc, and also Notes). But compare those encyclopedias to the amount of actual progressive storyline that he's written, and you will notice quite the sharp contrast regardless of the TM franchise topic. Tsukihime has itself, Kagetsu Tohya, a Tsuki 2 prologue, and a fandisc sidestory about two other Mystic Eye users, but at least 3 almanacs explaining vampires, magic, Atlas, Dust of Osiris, Archtype Earth, Satsujinki, and all the wear around them.
I mean I get it and it's fine to love the historical pokemon gimmick, but much like the waifu stuff I don't think it should've taken center stage when he doesn't have story content to back it up.
inb4 Wavershit. He didn't write that, and that novel and anime was complete ass. And much like FGO and Apocrypha, it breaks the foundational setting quite a bit.
>Sounds to me like you just have a problem with extended reading periods. KS is entry-level but still good, and especially remarkable considering how it came to be.
More like KS was boring and hardly relatable to me. I've gone through more eroge and VNs than I can even remember. KS was boring and, far worse, disjointed. They didn't engage an editor to smooth out the noticeable bumps in the various routes, Legless bunny was honestly the best time going in. Everyone else was just worse and worse.