Not particularly thrilled by this.
It really seems like WotC is trying to cash in on the very popular Baldur's Gate video game series, almost like they're riding BioWare's coattails. D&D has gone from the game that video games imitate and that video games adapt to the game that is imitating and adapting video games. (Almost as bad as comics, and their insistence on changing the source material to match the adaptation.)
Bhaal. Whee. The only thing interesting he did was die and do that poorly. He was only really active in the Realms for two years (1987 and '88) before dying when 2nd Edition was released. He's not exactly a fondly remembered god full of nostalgia and was rather redundant in the evil pantheon.
Hopefully, the Bhaal image and BG character are related to 2/3rds of the adventure being a detailing of the city of Baldur's Gate. A reference to the city's past and not its present as reflected in the adventure.