If you complete the game on a higher difficulty, you get the achievements from the ones below, so 7.8% is the total completion rate.
Still a 1.4% gain.
From what I've skimmed, a lot of people don't like Arx, so the loss can be blamed on content.
I doubt Arx is the main culprit. Look at the drops between the major sections:
- 57.9% escaped Fort Joy
- 43% reached Reaper's Coast
- 18.9% reached the Nameless Isle
- 14.8% reach Arx
- 7.8% finished it
Almost half of those who reached Arx didn't finish it, which is a bad sign, but the drop between Reaper's Coast and Nameless Isle is far bigger. Doesn't mean Reaper's Coast is the worst area, it's just the point where the factors that made people abandon the game peaked.
As I said in my original post, I believe the MMO design is the main factor. The series of large areas is a lot for most people already, and to make it worse, each area has specific enemy/loot level ranges. Players are heavily encouraged to explore all maps in a specific order, which makes progression a drag. And then you have the terrible itemization, constant inventory management, dumb armour system, bloated stats, predictable and constant battles, mediocre side-quests, tons of dialogue, bad humour, etc. I don't think there's any flaw that makes people actively upset, only things that add up over time and make them lose interest.
In the big RPGs Swen wants to surpass, players have a lot more freedom when it comes to doing side content, exploring or making progress in the main quest. In D:OS2, it's always clear that you have
a lot more of the same ahead of you, and all systems are designed in a way to make the player follow the intended path. The big RPGs have flaws as well, but they can rely on different things to keep players hooked. BioWare focuses on characters, worldbuilding, cinematics and production values. Bethesda relies on open world exploration, heavily streamlined mechanics, a short main quest and mods. TW3 is a BioWare/Bethesda hybrid approach but better at almost everything they do. Obsidian used to rely on reactivity, companions, and writing.
D:OS2 is not particularly good at any of that. Codex claims D:OS1 had good combat (I didn't play it), but that's certainly not the case now. The game does gets a lot of mileage out of the sandboxy mechanics and co-op, but that's not enough to retain players for 50-60+ hours.