SS is a number 10. CF is a number 9.
RvP's a better player than Welbeck. Nobody would deny that. Those stats are from last season alone, though. In that season - playing as a number 9 - Welbeck was probably the pick of the bunch. I think RvP had a poor season, disguised by a haul of goals that was inflated by set-pieces and penalty-kicks.
One season could be an aberration, of course. I'm just worried that they're trending in opposite direction, because of their respective ages. Tiime will tell if I'm right to be worried.
We don't play the system that allows a number 10 be a number 10, in the way Totti or Baggio played it for me, I've heard it said that we played with two 9 1/2s and that sums it up better for me. I barely trust 'untreated' stats, I'm running from those that have that level of subjectivity.
I added to the ppst above saying that if Welbeck's effectiveness was in such a limited area our attack, then he is not good enough for the fluidity required in my opinion. It's Kagawa all over again, if they are that good they must show some positional flexibility and it's up to them to fit in, not vice versa based on potential.
RVP is worringly crocked in my opinion, but the post above that said Wilson was ahead of Welbeck is more telling.