All of these new maps are just meant to be restorations of cut content that we learned about from screenshots, interviews or assets found in the game files. So they don't serve any real purposes, except maybe the Malkavian Maze shows the madness of Grout some more and provides a way to avoid the fighting in the mansion basement.
This is the key thing really, being stat-based the stealth in Bloodlines is about NOTHING except proximity.
This is not exactly true. Troika marked areas with lower visibility by hand-placed trigger areas that raised your stealth stats temporarily. Sadly they even managed to mess this up, as your internal stealth stat will stay increased after leaving these area, in case you accidentally saved the game there, making stealth easier and easier if you did.