The city has too much content as it is. Large segments that hold you back from progressing the main quest, at a point where you're expecting a climax in the story.
The sewers and bank robbery parts especially started being too much for me and I lost interest a bit. And the Minsc scenes were not good.
How many extra quests is there time to do when the Elder Brain is not fully controlled anymore and can break free at any time? Classic CRPG urgency vs side quests problem.
