I don't think you can read 1 Corinthians 15 as merely teaching "transformed into a spiritual being". Paul says 1) that Jesus was raised, using that as proof that there will be a resurrection of everyone else, and 2) that the resurrection body isn't like the pre-resurrection body. It's "spiritual" in the sense that it's fit for heaven.
That does not mean that Paul is teaching "transformed into a spiritual being". "Resurrection" doesn't fit for that. That's "died, and there's an afterlife". But over and over, Paul says "resurrection" - not just that there's life after death, but that there's resurrection.
Tabor's view seems to be forcing Paul's writing into a pre-conceived position, not letting 1 Corinthians 15 speak for itself.
I guess that depends on Paul’s use of the Greek word(s) we use for the English word resurrection. If the Greek literally means “raised up”, does that mean the body was reanimated, or Jesus ascended into the heavens? Paul doesn’t have any post-resurrection narratives of Jesus walking around in his reanimated body.
I can't comment on the Greek (at least, not right now), but Paul over and over talks about a body in this. It's a different body, but it's still a body. That's a huge focus of the discussion.
If Jesus "just" ascended into the heavens (as a spirit), Paul's discussion makes no sense. Paul clearly thought that Jesus had a body after the resurrection, no matter what Greek word for resurrection he was using.
It would be a spiritual body made out of pneuma, like the angels. Spirit meant something a bit different to the ancients. Pneuma was a substance. The supernatural was literally above in space for them. Why would a flesh and blood body ascend into the heavens where the spirits lived? Anyway, Paul had an ancient Jewish/Greek view of the cosmos, not a 21st century one.
That does not mean that Paul is teaching "transformed into a spiritual being". "Resurrection" doesn't fit for that. That's "died, and there's an afterlife". But over and over, Paul says "resurrection" - not just that there's life after death, but that there's resurrection.
Tabor's view seems to be forcing Paul's writing into a pre-conceived position, not letting 1 Corinthians 15 speak for itself.