SPOILERS AHEAD:
Perfect example of how bad the writing this had, was the death and episode of Illya. First she appears early on, just to play the cliche as all hell card of villain who will not defeat the good guys now but will come back some other time because reasons. Then she's pointlessly totally gone from the plot for the longest time, not because that would make sense, but because the plot demanded it,... just to be back for her death episode. So since writers didn't think any of this through they were like ''oh shit we forgot to develop her character or make her relevant in any way, quick, throw in a tearjerker flashback deathflag just before we murder her to get the viewers to care and get emotional''. This is just one example of some of the cheapest writing I've ever seen. And to find this in a show that is hailed as a masterpiece from one the most esteemed VN franchises of all time, just blew my mind.
I probably shouldn't even go into how little sense plot logic makes, with the Shirou Archer causal relationship and whatnot. But I wouldn't let mere plot logic ruin things for me,... rather it was Shirou's character arc that did it. Disregarding the fact he should have died in nearly every single episode, the story practically becomes about his internal conflict of wanting to be the hero of justice. Excuse me while I turn off this shounen red alert that just went of..... *click* there we go, now I can hear myself think again. Conflict where he is ''forced'' to face the fact that facing the fact that he can't save everyone (cause saving someone sometimes means not saving someone else) will make him lose track of this childhood ideal of his. Yes, read that sentence again. No, it still doesn't make sense. Plus it's somewhat of an irresponsible message hinting that change, as in growing up and changing your mind, is bad. While this can be an interesting and meaningful theme, I can't imagine it being dealt with worse than here. It basically came down to not wanting to grow up being a good thing somehow? Otaku pandering much? Like, suppose your adult self traveled back in time and told you you're wrong about some things. You'd be sane to believe him right? Providing you know the situation to be genuine. But no, not in Fate universe. Here, spouting shounen nonsense at your older self actually makes you fight stronger! Ooh, our shounen protagonist has to deal with drama and character development and whatnot... oh wait, that doesn't automatically make said drama and development any good whatsoever. Who would have thought? And by the way, your reward for being a dumbass shounen protagonist is this super awesome girl that likes you because this was originally a servicey VN in which heroine has to fall for the protagonist regardless of it making sense.
Not that I mind having romance, in fact, watching Rin be Rin and go all tsun tsun in various SoL situations pretty much made the show. Well, that and the out of this fucking world animation and production budget. Based ufotable. You made this clusterfuck of a story watchable and occasionally really enjoyable, kudos. You deserve Mt.Fuji sized cookie.
And to go on a slight tangent: Fate/Zero on the other hand is basically Urobuchi saying ''oh look, cool premise, let's see how it would look if writing didn't suck''. But even then, fantasy shounen-ish setting can only get you so far, hence why first season for both is a bit disappointing, mainly due to all the status quo-ing. Zero gets rather awesome in second season, while UBW tries to get awesome but falls flat on it's face, still somehow managing to at least stay interesting enough. Actually the reason I enjoyed second season/half of UBW a bit more is due to both more pretty action, and story becoming more complicated, so keeping track of all the nonsense that's going on was actually rather amusing. Plus the nonsense got even more nonsensical, in a ''so bad it's good'' kinda way.
