Returning viewers get the cast chemistry, escalating problems and lovingly familiar personalities they have missed. The film is particularly rewarding when you already know the relationships.
Pros: celebrity cameos, humor
Cons: pacing, ensemble balance
Established fans get recognizable humor, relationships, and callbacks, though the weaker deduction work and reduced Sherlock presence could disappoint.
Pros: entertainment value, lead performance
Cons: mystery quality, pacing