I have seen ONLY a few people perform well with words in front of them.
I would rather see any singer sing without words even if they have a small repertoire, even if they have sung the song many times before, in my experience if they are any good as a singer they will interpret differently every time.
I do not accept that because someone is a floor singer, and has small repertoire that they will not be any good, which is kind of implied in this statement
"I would rather hear people trying new things, even if it means using a book, than trot out something from memory that I've heard them do five times before. (I fact there are very few floor-singer numbers I'd even want to hear twice)."
However, EACH CLUB organiser has to decide what is right for their own club, people vote with their feet which clubs they wish to attend.
   I would be more inclined to turn up at a club, that stipulated a quality control, I am sure there are others who would do the opposite.