I am having trouble parsing his complaints.

IMHO he has at times been a brilliant songwriter and/or poet, but when he simply talks he is often disappointingly inarticulate.

Anyway, if he likes what he hears in the studio better than what he hears on the product, I interpret that to mean that his problem is with the mixing.

Call me naive but I am surprised to hear that an artist of his stature does not have control over the final mix. If I didn't like what the engineer was giving me, my first impulse would be to get a different engineer.