You have to give the album a chance to unfold. A comparison with the predecessors should not pull you. One should also keep in mind, there is a studio album and a hangover are known for their spectacular live shows.
Personally, I understand the poor to mediocre reviews from many others do not, unfortunately.
"A Kiss before you go" was initially criticized, until it was wound up liked by everyone.
Give "Rockland" a chance and you hear it twice, three times and if necessary even at times.
This album is definitely a worthy successor and receives from me a strong buy recommendation.