Art is such a subjective thing so it makes sense that what that art is likely to look like is approved by members via the committee. Picasso? yes. Marilyn Manson? probably not. The artist should be able to present former work or a pencil rough/draft on what is proposed to give you some heads-up on what the outcome is likely to look like. You’d also want to know the budget and know how long the works may last if it’s exposed to the elements.