After the first 4 books, I was expecting a book which would be good light hearted fun like better descriptions of Diagon Alley, more on the Weasley household.
But the book right from the beginning has dark and gloomy undertones.
Further Harry Potter and Professor Dumbledore seem to be rushing to bring matters to an end. Snape’s charecter is not fully fleshed out - Professor Dumbledore shows faith in him till the last moment.
The author does not properly explain how Snape went over to the dark side. Certainly, it could not be because of the influence of not very ’’dark’’ chaps like Draco Malfoy and Co.
The love angle in the book (too many pages) is very ’’wham-bam’’ish with the maximum references to ’’snogging’’ and something else very puerile (I don’t remember now).
Further, Harry Potter’s wizard vs. Muggle feud (his Uncle Vernon +) is not elaborated. That was always very funny.