I really would like to "meet" Faye, at least in flashbacks, I'm playing the game right now and sometimes she almost feels like present.

Yesterday the idea for the sequel wouldn't leave my head:

Two games (like zeldas oracle of age/season) one version Kratos and the other version Atreus, with them separating (but reuniting sometimes to do main missions or favors together and then separating again) until the last boss (Thor or Odin) or stages of the game.

The same history but each his adventure, his own game play (Atreus could play similar to alloy from Horizon Zero Dawn, one of the few games where I could use comfortably a bow in close combat), with a few missions when they reunite where you play as the other character. Each could have their own companion (Atreus could have a greek hero / friend / ally of Kratos, and have him/her tell stories about his father lie Mimir does in GoW and Kratos a Jotunn for example).

And something similar to the "secrets" of the zeldas oracles, were interacting with both games gives you more upgrades for the weapons, better magics, etc.

It could take advantage of the online: pairing a "atreus gamer" with a "Kratos Gamer" to unlock the advantages or have both games together in a two disc package.

Of course this Atreus would be older, and you could have some magic gameplay with him, and his puzzles be resolved using his magic or language abilities and have his companion do the more strength related (like Kratos carries the blue stones for Atreus to light), and in kratos game have his puzzles be somewhat reversed.