guest_1440959966322 :
There should be a penalty. When do you ever see a no. 8 playing at 15 or 11?
Just because the number of better players are of a few position numbers doesn't make it right.
Be more real game like not just about figures on any player for any position.
In 'real life' outside of props and hookers, plenty of players have played in different positions. Although even then Ben Youngs started as a centre before becoming a hooker.
Using your example, the Great Jonah Lomu played as a no.8 and winger for instance. More recently Sam Burgess played as a 7 for Bath and a centre for England. Like in 'real life' if you train the players correctly they can change position.