In part because of a reluctance to insinuate that Wilco might be past their prime, obituaries for Jay Bennett, the former Wilco multi-instrumentalist who died in his sleep yesterday of unknown causes, have downplayed Bennett's contributions to the band. So here's some context: Bennett played on Wilco's three best albums (Being There, Summerteeth, Yankee Hotel Foxtrot, taking on increased responsibility, songwriting and otherwise, on the latter two).
While nobody would argue that anybody other than Tweedy was the creative force in the band, I'd contend that it's no coincidence that the group's albums lost much of their wow-power after Bennett left the band ("left" might be too gentle a term, considering the acrimony behind his exit).
Tweedy put out a graceful statement about his old bandmate today, one that may even imply apology: "We will miss Jay as we remember him — as a truly unique and gifted human being and one who made welcome and significant contributions to the band's songs and evolution." That Tweedy acknowledges Bennett's contributions is important, given that they're the subject of an ongoing lawsuit.
But how could he not? One need only compare Summerteeth to Sky Blue Sky, or Yankee Hotel Foxtrot to the new Wilco (The Album) to hear for themselves how integral Bennett was to the band.