I finally managed to finish this game and decided to report here. My opinions of the game have not changed that much, unfortunately.
As I said before, the setting was very interesting and I bought this game because I wanted a game with an amazing story. I was hoping this game would've made me feel like only three others have before, but it didn't. Chrono Trigger, Final Fantasy VII and Grim Fandango left me a feeling of "That's it? I don't want this game to end. I want to experience more adventures with these characters." At least the idea of an immortal person, having lived for thousands of years and losing his memory was something new. For some reason I find events spanning millennia and their effect fascinating.
I played the game with high intelligence, wisdom and charisma. I tried talking to people a lot and completed almost every quest I could find. From my previous starts I had noticed that the combat is boring so I set the difficulty to easy instantly. It didn't make the combat less boring, but at least it didn't last as long. Although I micromanage my party in the Baldur's Gate games, in this game I dropped it since for some reason I found combat very uninteresting, especially towards the end. Mostly I just ordered everyone to attack and rarely used spells. This might be due to the horrible user interface. Selecting spells and thief skills worked much better in the BG series.
Sadly the story progresses far too slowly and the side quests are often not very interesting. I was probably enjoying half of the dialogue and events the game had. Until finding The Nameless One's tomb in the Drowned Nations, nothing interesting had happened plotwise since speaking with Dhall in the Mortuary. The story of Ignus in the Smoldering Corpse Bar and some conversations in the Dead Nations were the only interesting things before that.
After leaving the Hive the game got a bit more interesting with its side quests and dialogues. The siege tower and its contents in the lower ward were nice to play. The Clerk's Ward provided even more interesting content and I enjoyed the brothel, the sensoriums in the Civic Festhall and the imaginative items in the Curiosity Shoppe and the Galleria. This was probably the most enjoyable period of the game for me. Soon after, though, starting from Curst, the game became very boring until the last few places.
I really wonder if the places in and after Curst, until the Fortress of Regrets, could have been combined into something nicer. Curst doesn't offer anything interesting and just makes you run back and forth completing mundane tasks of talking and fighting. Sure some of the things you do affect the situation in Curst prison and Carceri, but otherwise it lacked any interesting people to talk to or other activities (did it even have side quests?). When I get to Curst underground the game starts repeating a pattern; fight through a map of hostiles, get a tiny bit of info and find a portal to a new location. Repeat a couple of times. Why so much fighting in the end when its the worst part of the game?
Finally, after being thrown into a pool of tough enemies, running from them, getting killed, running back into the pool from the other side of the map, having to run from enemies again and finally finding a way out at some point, the game becomes interesting again. The ending was not as epic as I expected, but the choices you can make were nice and it felt right. Especially the conversations after Ignus were very good.
I don't know if I'll ever return to the game again, but if a sequel is made (suggested if the BG EE is succesful) and it gets praise like this game, I'm likely to get it. I can also recommend everyone to try this game, as it is very original and all those people loving it can't be totally wrong, right?