Your picks of mediocre or lousy vocals with great musicians!

Jim Morrison? Wait a minute! Aren't rock vocalist SUPPOSED to be lousy?

Mapman,
Mick Jagger isn’t mediocre vocalist. He’s lousy and always off the key.
Not attracted neither to Bob nor Mick, but would love to hear Dylan’s songs performed by great jazz vocalists rather than Dylan sing himself. Not his job IMHO.
Just me or maybe not.
Dweller,
Yes. The rock vocalist MUST be lousy to the point of goose bumps on skin sounding similar to opening of the old rusted shed door or grinding noise of breaks with worn pads! Axle Rose I guess is champion.
Can’t tell that about Jim Morrison, Peter Gabriel or even David Byrne.

The Byrds did wonderful versions of Dylan songs. 

Can't think of any other Dylan covers I enjoy as much as Dylan's.

Dylan's is a case of an effective voice.   Not good at all rally technically.  He's also not a great musician either some in the know say.  For all it matters.

I would also rather hear Lemmy sing his stuff than anyone else. Its a unique though technically flawed instrument as well.

Then of course there is the case of the man Johnny Cash himself.  Often a great but limited and flawed vocalist who probably would be thought  of lesser if any other way.

The Grateful Dead and Phish all members.