I have played the VN back when it came out, I watched all the adaptations of it including this one when they came out. My impression for a long time has been, Shirou is an extremely edgy teenager that always conveniently gets saved by plot armour, ends up with the hottest waifu, all while preaching his "friend of justice" dumb ideal. However recently having close studied Fate Zero, Unlimited Blade Works, as well as Heaven's Feel, my perspective have changed somewhat. I was able to understand why this series have become classic holy text, it has a very strong and consistent emotional core.

Let's start with the worst, edgy chunibyou protagonist Shirou just loves swords, everything is about swords, even the title just says unlimited swords, instead of blocking ranged attacks with a simple shield, they have to use a sword to parry it. it just feels so immature and edgy. Protagonist Shirou is also always preaching about saving everyone, serving justice, leave no one behind etc. Yet it always seems like by "everyone" he means drop dead gorgeous anime waifus and cute loli, and yea, of course he's gonna save those people, I would too, so would any man, who can resist Saber's shoulder blades, Rin's Absolute Territory and Sakura's E-cup right? Is he really serving justice or is he just serving something much more private?

Then there's the writing, mid-season they needed to have Saber out of the way for power balance reasons so they put her in a sexy dress, in bondage and she just passively stays that way until it's her time to fight again. It doesn't fit her character, it doesn't make much mechanical sense because nothing like this ever happens with other servants in this route or any other route. It doesn't make sense the bad guy just wastes Saber as an NSFW life-size figure for decoration. And there's more stuff like this, not as bad but just rough and not well thought out.

However, despite all that, my favourite thing about this show is the epilogue, because it reveals some truth I have not previously realized when I was too distracted by the aforementioned problems. This story is really much smaller than it pretends to be, which is a good thing, because that small story is emotionally true, consistent and strong. On the surface it seems to be about an existential crisis, or at least existential for this one Japanese city, it's about life and death, saving people, leaving them to die, fighting literally to the death for ideals etc. Instead what it really is about, Shirou's teenage struggle with his ideals, and a relationship with Rin, when they look back later at all this chunibyou nonsense, they will realize it was actually quite insignificant. This re-interpretation in the end rings quite realistic to me, many people had at some point, an illusion of grandeur, when we were young we tend to think the problem we're facing now is life changing, is now or never, they seem so incredibly important. Yet when we get older and look back, our past selves start to feel silly and inexperienced. Unlimited Blade Works in its core is actually about that exact feeling.

The best moments of the show are definitely about Rin and Shirou, I would say this is the best relationship route in FSN. Even though Rin won't admit it because she is tsundere, she is also a "friend of justice" you could say, so this couple just feels right in a way others do not. Sakura is a perfect housewife she could be married to any man. Saber is, well I guess everyone must know at this point, she's secretly some 30 years old veteran and king of knights, would she really date an edgy teenager? But for Rin it is again emotionally very plausible that she will stick with Shirou. There are some convenient developments as mentioned but it wasn't too hard to see how the same effect could've happened in more grounded ways with just minimal change so you shouldn't be too bothered by them.