Have you ever listened to the Zep live album The Song Remains The Same? They sound huge. So I’m not sure the critical piece is Robert Plant’s stage antics.
RE Plant scrubbing the reunion, I’ll bet if you could really get inside his head, you would find that there’s some kind of an issue with Jimmy Page at the bottom of it. I’ll bet Page kind of wanted to run the show but Plant didn’t feel like submitting to that again.
http://www.thegardentapes.co.uk/tgt.html
Here is an analysis and deconstruction of how songs within “Song Remains the Same” were pieced together from different concerts and had minor overdubs