This sentence is from Edgar Thorpe's Objective English.
As I know, we should use the comparative adjective to compare between two entities and superlative adjective to compare among three or more. But in this sentence, it is not clear to which 'the new office block decoration' is being compared.
So is it fair to assume the speaker is comparing 'the new office block decoration' with more than two entities and use superlative adjective and write:
The decoration of the new office block is most pleasing.
Even so shouldn’t a superlative adjective be always preceded by 'the'?