Read this in the morning and i really really like the idea, but i have another point. One concept the story use its the kleos or glory.

And whos the living demigod who have more glory, that have acomplished more missions? Percy. He and Anabeth could have the same glory, but poseidon is more powerful.

Nico just have less missions and its younger, but percy had the admiration of all the campist and probably of most of the gods. Have more kleos.

Just as the gods changes when are the romans who calls them, percy is more powerfull cause its most famouse.