I think that certain positions, and therefore certain numbers, are more fluid than others.
1, 2, 3? Prop, hooker, prop. No doubt about it. Folau in a 3 jersey would be out of the question.
4, 5? Second Row. Folau would look ridiculous in these.
9? Halfback. 10? Flyhalf - primary playmaker.
All the above are obvious. Why? Because they all have obvious and clearcut individual roles.
Where there isn't a clear cut individual role I think it becomes more blurry.
6, 7, 8 just don't have the cookie-cutter roles that they used to have (despite the desires of some of our *perhaps older* posters).
What really is the role of the 6? Or a 7? Or an 8? Well you have to look at each player in each position in the context of the role the back row has to play as a collective whole.
The backrow has to supply atleast one lineout jumper. The back row has to supply ball runners, both tight and wide, and players to secure the ball (again, across a few different channels). They have to be fit, high workrate players, and have to be of certain physical attributes. If they're not of certain physical attributes, they have to play like they are (Hooper, McMahon). One of them has to pick the ball up at the back of the scrum with confidence and deft hands.
In essence, as long as you can find 3 players who fulfil all of the above between them with a healthy balance of all the required skill sets, it doesn't really matter which one wears 6, 7 or 8. In fact, if it helps your game plan, you can have your 8 pack down at one position on offensive scrums, and another on defensive scrums! It's entirely up to the coach.
I think its similar in the backline. Yes we need a halfback to get to every ruck, provide direction to the team and provide crisp ball. Folau would never be seen in a 9 jersey.
Yes we need a flyhalf to be the primary playmaker for a team, to direct the traffic around the field and provide a ball running, ball playing and kicking option.
But from 11-15 it becomes more fluid. What do you need from these players?
I think you need strike runners, people who are damaging with ball in hand and who can bend or break the line.
I think you need a few ball-players, a few kicking options and I think all of them need to be solid defenders.
Where you play them is up to you. In fact, where they line up in offence and defence will be entirely up to the game plan and the unique attributes of each player.
England doesn't field the same types of players / composition of players that we do in the backline nor the back row. Neither does New Zealand, nor South African, nor Argentina, France, Scotland, Ireland, Uruguay, Madagascar or the Nudgee u15s.
Billy Vunipola is a very different player to Kieran Reid. Matt To'omua or Kurtley Beale are very different to Ma'a Nonu or Jamie Roberts. Malakai Fekitoa is certainly different to Conrad Smith.
It all depends on the cattle available to you and your own game plan.
Its time we stop caring so much about the type of player in a jersey of a particular number. The games moved on, so should we.
