As someone who really liked Jason in his debut book, The Lost Hero, I can not in good faith pretend that he is a well-written character:
For a main character who was raised by wolves (basically a feral child), abandoned by his family under dire circumstances, lived as a soldier in Camp Jupiter and suffers from amnesia, his characterization is mind-blowingly disenchanting. Just think: struggling to communicate with his new found friends, trying to keep up with the new socialization needs, attempting to figure out his interests, values and beliefs. There was a plethora of avenues for exploration
His scope for fatal flaws. Sure, he does have some flaws, but it could've been executed so much better. In the Mark of Athena, the conflict regarding Nico's fate could've established his fatal flaw as excessive/blind caution, or occasional harsh insensitivity. Because, let's be brutally honest here: Nico was doing his job as an ambassador by keeping secrets (the gods themselves kept the two camps apart). His suspicion of Nico was not really valid, and could've been utilised effectively (this isn't the only time Riordan drops the ball on Jason's potential fatal flaw, by the way).
In House of Hades, his writing left a lot to be desired. The quest for self-identity being tied off to a choice between the two camps had potential, but it also encroached the other ways said quest could've been written. Aslo, Riordan's execution certainly missed the mark.
In Blood of Olympus, his writing starts on a promising note, with poignant (albeit very late) insight into his abandonment issues. Said issues, however seem relevant only for the first few pages; by the end of the book they're already forgotten. Unfortunately, the remainder of his PoV chapters in this book are more akin to page-filler than actual substance.
Me writing this stuff down
