Page, Plant, Jones and Bonham may have plundered the back catalog of various folk and blues artists of the past without due credit, but boy did they do it well.
You could argue that this is an activity very much in the folk tradition; the music has freedom, songs get passed from generation to generation, and are interpreted differently. Page is criticised for stealing Bert Jansch's Black Water Side, but really Page and Jansch were both inspired by Anne Brigg's interpretation of a folk song which is much older than any of their versions.
From what I can gather from the reviews and bootleg footage of the gig (I wish I had been there), the band returned to their roots; just the four of them, some instruments and some Marshall stacks, like they were back doing a TV studio recording in the late sixties.
After a number of poor reunion gigs over the last twenty-seven years - especially the Live Aid reunion - they proved that they could still perform at a level similar to the their early gigs, and being a life-long Led Zeppelin fan, I'm glad about that.