Quest tracking is pretty loose I agree, but this problem isn't obvious until you get past Cyseal.
Once you left Cyseal, you'll realize how bad it gets. I literally had to rely on my co-op partner to guide me through cause it was impossible for me to keep track since I was uninvolved for most of the conversation.
In fact, I felt Larian want to make the game slightly open but as a result, many players went to areas out of sequence, faced enemies above their levels and get wrecked. Or encounter puzzles that they may not have a ready solution.
All I can say is, cut down on the puzzles - and less of a huge map where parties have to have to find a specific item to fetch. Make it more focused and compressed like Cyseal. And don't derail the players with too many details like telling them about THE END OF THE WORLD when they barely started on their first murder investigation.
