I love Valetini's involvements, he can really hit and dominate in carries, tackles and cleanouts. Having watched him a bit though, he really needs to be more involved. He could be a seriously dominant player. This is a bad example because I know Wilson must have played more minutes than him, but just as an example, Wilson is listed as having over twice as many carries and made 50 more tackles than him throughout the year. Unfortunately I don't have ruck stats but from watching, I would not call his work rate there high either, very effective for sure but not high.
Valetini is awesome in what he does but he would be so much better if he lifted his involvements a bit. Still, wouldn't be unhappy with him at 6.
Edit: Having said all that I'd love to see
6 Valetini
7 Hooper
8 Wilson