Last look at Yourcenar's Memoirs of Hadrian: I must be missing something

Ultimately (though I didn't read the whole novel), Marguerite Yourcenar's 1951 novel, Memoris of Hadrian, falls short by being "neither fish nor fowl." If you want to know the facts about the life of Hadrian why not read a nonfiction, scholarly work - as this format of a fictional memoir allows MY to create and change facts and offer suppositions as she sees fit (based of course on her serious research). If you want a great novel on historical themes, however, you probably should find something that focuses on a moment or period of crisis or a fraught relationship - something like one of Gore Vidal's historical novels, or The Executioner's Song in a completely different vein. The problem w/ MofH is that there's too damn much material, and by writing about Hadrian's entire life MY never finds a dramatic scene of relationship. Props to her for her honest and forthright inclusion of Hadrian's homosexual relationship with a very young man, Antinous, who commits suicide to show his enduring love of Hadrian. Or so Hadrian thinks - a little more self-reflection on his part would have been helpful. The novel takes the form of a 300-page letter to H's successor, Marcus Aurelius; as such, the memoir is really H's apologia for his own life. It would have been a stronger novel, I think, had it been his Confessions: he leaves MA a find account of his benevolent reign over Rome, but there's not a moment of guilt, hardly a passage of secret intrigue, just one successful campaign after another. I'm surprised that so many consider this work MY's masterpiece and a great work of 20th-century fiction. I must be missing something.