An Unlikely Avenger? Harold Bloom argues that "Hamlet cannot strike us as a likely avenger, because his intellectual freedom, his capaciousness of...

Hamlet isn't
sure the ghost is what the ghost says he is.  So, all the talking is the result of this
uncertainty.  He is looking for proof...proof of Claudius' guilt, proof of his mother's
involvement, proof that ghosts can come back and give orders as they were accustomed to do in
the living world.

He is being cautious before he acts too rashly and is
proven to have been mislead by the forces of evil.  Had Macbeth been less quick to act, his
"end" would have been less tragic.