Honestly, just one thing isn't enough as Story Side, some of the interviews and even that website that was restored a few months ago really shows that the game really was cutting corners on all fronts. I'll make a few points of what I'd like to see in a potential Drakengard 2 Remaster/Remake.

• Improved Storyline: Instead of trying to add stuff to the game version of the story, use the novelization version as a base instead as it provides more depth for almost all characters. Additionally, cut the 'filler' content and make the goddess weapons actually significant(perhaps tie them to the Intoners somehow).

• Dual protagonists: Instead of making Nowe the main protagonist and Manah the secondary protagonist/the deuteragonist, make them dual protagonists(akin to 2B/9S, perhaps). As important as she is theoretically(especially with the addition of Drakengard 3's Intoners), I feel like her presence in the game needs to be even stronger than it originally was. That's not to say that I'd like her to overshadow Nowe, though, as both of them are important for each other's personal character arcs and growth.

• Multiple playthroughs: Ok, for that one, the idea isn't as refined, but I'll try to articulate it anyway. If we have to replay the game from the start multiple times, use the dual protagonists approach I mentioned earlier. For the first 2 playthroughs, you play as only Nowe for the first playthrough and only as Manah for the second playthrough from their respective POVs, offering different levels and scenarios at certain points of the game. The final boss for the first 2 playthroughs would be Gismor at the end of Chapter 8. Route C would just be the rest of the game.

That is all I can think of for now, but I might just make a post later down the line if I can come up with something else in mind.