Prince Lestat and the Realms of Atlantis

Was there really a need for introducing aliens in the books about vampires?
Once again there are lots of new characters. However, they suffer the same treatment as in the previous book. They hardly have any characterization and they just feel flat and one-faced. It does not feel like t hey had any built up and might as well have been not existent. Atlantis had so little to do with the story, and it would have interesting if this side of the story was expanded and done more coherently.
The only vampire who had some characterization was Lestat, while all the other vampires that used to be so compelling and charming in previous books became just background scenery in most scenes. There was a try to create so tension and drama with Armand's hostility towards the Replimiods. But the potential conflict just got nowhere, it was neither resolved nor acted upon.
As for Amel, he was more intriguing as a spirit summoned by Mekare and Maharet, than as a Replimiod. There was some mystery to him, which was shattered in this book.