Would anything be lost if the gravediggers in act 5, scene 1 were omitted?

Any answer to this question is always going to be subjective, but I would argue for the scene's retention; the reason being that it serves to highlight Hamlet's growing preoccupation with death.
Earlier in the play, Hamlet teasingly suggests to Claudius that the worms which feast upon a king's corpse can easily pass through a fish, and then into the digestive system of a beggar. And we see a similar theme here, only the gravediggers show an even more irreverent attitude towards death than Hamlet. Their badinage, painful puns, and witty wordplay add a humorous gloss to what really ought to be a deeply solemn theme. However mighty we may think ourselves, we will one day all suffer the same fate—high or low, rich or poor, king or beggar. This is what Hamlet was driving at when he played his mind games with Claudius after killing Polonius.
The gravediggers, like Hamlet, have a profound sense of the fundamental absurdity of human existence. In the face of what they regard as a meaningless universe, they feel they have no choice but to make merry; for tomorrow, they too may die. The gravediggers' gallows humor sets up Hamlet perfectly, allowing him to take up Yorick's skull in his hands and embark upon another of his great soliloquies, articulating with great eloquence the same insights expressed earlier by the gravediggers, albeit with considerably less refinement.