They only allocate 2 seats per flight in Biz and 1 seat in F on their Long Hauls. I have yet to see them releasing more availability even if the flight is empty. (has anyone managed to get that 2nd F seat?)
To be honest with you I feel the miles + the vouchers that you earn kind of make up for the high redemption rates.
Over all it's not a bad program if you can book in advance. Or else they do let you stand by which most programs don't.