Pretty much everything I dislike about them. I guess if I was walking in open fields and had a dog that couldn't be off-leash they might be useful. I think they are completely inappropriate where there is contact with other people/dogs/traffic, and are far too much of a pain to untangle from the brush in the woods.
I wholehartedly (sp?) agree with you. Even with a dog that can't be off leash a longer leash would do well. I have a few of the leads that are used for horses, not sure what they are called. They are great, about 20ft and I can shorten them as I need and have total control over my dogs.