I’m with Alex Johnston on this one, but I will add that;
- In late 1973 he had had enough of touring (not Alex Johnston) & approached the manager stating that unless thing changed – he was leaving the band! Along with Jimmy Page, the manager did not dare inform the other 2 members – they concerned themselves with how to continue on without him; in the end, Peter Grant honoured JPJ’s requests & scaled back touring to appease him – does that seem as if he was the “weak link” to you?
- After (Fairport Convention vocalist) Sandy Denny’s demise (R.I.P.), John Paul Jones performed her “The Battle Of Evermore” contribution in concerts – whilst playing an instrument! “Weak link” anyone?
- Due to personal (Plant’s physical/emotional mishaps) & drug-related reasons (Page’s by then well established heroin addiction; Bonham’s alcoholism is irrelevant here), when it came to recording the band’s final studio album the 2 principle songwriters were bereft of ideas – so guess who came to Led Zeppelin’s rescue?
That’s right, John Paul Jones. The material he had previously been tinkering with may not have been exactly suited to the band – but it was either that or spend the next however-long-it-takes to write new material. It was John Paul Jones’ time to crack the whip!
Sort-of-disclaimer: Even though this nifty little instrument was not used on Led Zeppelin’s final studio album, it does demonstrate that there was more to John Paul Jones than ‘just the bass player in the background’.