The Welsh National Opera is producing a radical version of “Carmen.” It’s short – clocking in at about an hour long. “Its short span is not the only unusual thing about this production, which is currently on tour. It is also radically cheap – tickets cost £5 and £10 – and played at unfamiliar times. Performances are at 2.30pm and 6.15pm: the afternoon show is designed to allow visiting parties of kids to be back at the school gates by home-time, and the early-evening performance is aimed at an after-work crowd.” Will this really tempt people to get the opera habit?