Google+ vanity URLs make me like Google+ less

I prefered the unique-ids. Which url does John Smith get? Does he get +JohnSmith, and what about the other JohnSmiths? Will they have to put up with +JohnSmith2 and so on? This becomes a little silly and doesn't really bring anything.

Are these urls user definable (outside of picking your original name)? Can they be changed at a later date?

It just gets silly, and doesn't really bring anything. Who'll write them in manually too? I prefer something more ambiguous. Perhaps a search for: 'John Smith, Manhattan', or 'John Smith foobar inc'.

What happens if you get married and change your name? What happens to previous urls without the vanity name?

Can I roll back if I don't like it? If I don't select my vanity url, will someone else get it?