Duets or ensemble pieces work only if everyone is on the "same page". Bono was able to work with Sinatra so well, even though Sinatra sang the song very straight-forward, because Bono just slightly enhanced the song. His additions were at perfect places (like the falsetto over the big horns) or the slight changes in lyrics (something Sinantra has even done when he has performed duets). In other words, even if you call Sinantra the "straight man" here, the two were on "the same page".
The same is true with many other duets that U2 or Bono have done. For example, the duets with Robbie Robertson (new perfect), Clannad, BB King, even the Corrs.
But with this remake of "One", we have two big problems. First, it is one of U2's best songs. We've only heard U2 (or Bono) perform it for 16 years. We have that sound in our minds. The second problem is that the song starts out the same U2 way. Then along come Blige and she's on another page completely. She's taking the song to places that does not flow with the U2 version.
There's nothing wrong with that, necessarily. In fact, I often appreciate remakes that aren't exact copies of the originals. Anyone who makes an exact copy is just trying to cash out - they know the song was a hit decades ago, they figure it'll be a hit again. But those who revamp the song and "make it their own" (as so often said on "American Idol"), get more respect for me. So in that sense, I do appreciate what Blige was trying to do.
But combine her "out there" version with U2's and they just don't blend. This isn't like Bono's slightly alternate take on "Under My Skin" with Sinatra - Blige was in another world with this song. And really, it changes the subtleties dramatically. This was a song about pleading, about desperation, about that last bit of hope. Bono's scratchy album version vocals were perfect. But Blige's over-the-top performance made this song into something else - I'm not sure what, but that focus is lost.
And I think for this reason, the duet fails. It might have worked better had Blige been alone on this remake. We could have all hated her version, but at least that's what it is - her take and ONLY her take on the song. But combining the two styles only causes confusion and decreases the focus of the song.