Easter is utterly central to Christianity. "God raised Jesus from the dead" is the foundational affirmation of the New Testament. About this Tom and I agree. We also agree that the best explanation for the rise of Christianity -- indeed, the only adequate explanation -- is the resurrection of Jesus. We also agree about its central meanings. Put most compactly, I see the meanings of Easter as twofold: Jesus lives, and Jesus is Lord. Both claims are essential: Easter means that Jesus was experienced after his death, and that he is both Lord and Christ. Though each of us might add further subpoints of meaning, we agree about all the above.
Where they disagree is in the manner of that post resurrection experience of Jesus, that is it's historical grounding, but they agree that without the resurrection there is no Christian faith.