If Shirou's character wasn't in a battle series with chuuni magical elements in a niche Japanese medium he'd be marveled as a literary masterpiece, a modern Hamlet that defines modern protagonists. First he'd need to be moved into a story without magic, and instead his backstory was that he was a survivor of a terrorist bombing 10 years and was then saved by the terrorist who planned the whole event. Then you could replace all the magical backstory with political elements and set the story in the Middle East, replace the Holy Grail War with a regular war, etc. If you had a more "serious" story that people didn't judge on the fact it had porn scenes and was from Japan, people would be regarding Shirou as one of the most interesting protagonists of modern literature. This is a fact that none of us can escape from even if we insult Fate as a chuuni eroge.
Sincerely,
General Kian the Not-so-Hidden.
Sincerely,
General Kian the Not-so-Hidden.