Prince Lestat

Finally, the Vampire Chronicles are back to the origins with very similar feeling to the first three books.
All the old vampires have the reason to come back together, however they felt like a collection of faceless individuals to form the backdrop of the book and provide the necessary numbers in support of Lestat. When they are in the same room, they rarely interact with each other, as though the histories between them is inconsequential. The established characters are accounted for with only a brief remark. Most of the cast just felt underused.
Their role as supporting characters is overshadowed with the introduction of several new characters. Other ancient vampires are introduced, none of whom are interesting or different from the current caste. The addition of Rose and Viktor felt random and hardly needed, even more, what happened in the ending.
Rhoshamandes, as secondary antagonist, could have been developed more, more of his history, more of his motivations could have been shown (and not just chalked up to ‘the Voice made him do it'). For most of his appearances he goes on how much he hates Armand and how he wants to kill him. However, they are finally in the same room, Rhoshamandes seems to just forget all of his hatred (of course, at the moment there are more pressing matters, however even a small reaction to seeing Armand would have been interesting to see).
Also, for being the oldest vampire in the current era, and closes to what Akasha was like in The Queen of the Damned, Maharet does lose very easily to a far weaker vampire. The Voice's motivation for everything it does in the book is very cliché and it is forgiven very easily.
Lestat has lost some of that razzle dazzle over the years, he's become less interesting. He does not feel like the Brat Prince of past.