So with the selection of Tomkins as scrumhalf, the question is does a scrumhalf need any specialist skills or are scrum half , stand off and fullbacks totally interchangeable?

No, some half backs become hookers and vice versa. Some full backs become wingers or centres and vice versa. Some half backs become loose forwards.

Some examples:
Greg Inglis, centre to full back
Michael Monaghan, scrum half to hooker
Darius Boyd, winger to full back
Stafan Ratchford, centre to stand off to full back
Sean O’Loughlin, loose to stand off to centre to loose

There are probably dozens of examples.

The main thing being that sometimes it’s just that there’s an injury in a team that means you play your most closely matched player or a player where he has a good replacement with strength in depth in the position that has nobody in depth.

There are players who are purely a full back, scrum half or hooker; the best examples are the big three Melbourne/Queensland/Australia players Slater, Cronk and Smith.

But a lot of good rugby league players can play across many positions.

Even in football City’s goalkeeper, Ederson, used to be a left back... Chris Sutton was a centre half and then was a centre forward... they are bigger changes in skill set than any change in a rugby league or rugby union position.

I've seen Silesi Finau play prop and right wing at Wilderspool.
As regard to half backs, the game needs some with handling skills and vision to make it interesting again.

Harvey Howard for a total position change

It's a reflection of the utilitarian make-up of squads theae days. Coaches these days prefer jack of all trades who can [iplay[/i in many positions rather than [iexcel[/i in one.

This is nothing new : Hanley, Schofileld & Davies played in a variety of positions because they were hugely talented athletes whose core skills allowed them to adapt.

The problem in the modern era is we have utility players who, due to the overall decline in the quality of attacking play, can make do.and.mend in key positions.

Hence we have average full backs becoming appalling wingers, average full-backs becoming average half backs and mediocre half backs becoming round pegs in square hooker holes.

Putting me in pink diamante glasses doesn't make.me Elton.John any more than hoofing the ball in the air on tackle.five would.make me Alfie Langer.

...and there we have today's SL in a nutshell.
Blokes who (just about) can play in most positions, do play in most positions, bar a small scrum half going as prop.

Coaches want their players to be athletes, rather than RL players. They (the players) all seem to be an identikit 6'1" 14.5 stone, lean mean (non fighting, 'cause that would be naughty) machines
The games crying out for a wiry built winger, a la Phil Ford, who could step out of a tackle and be away, rather than another [ibrick pooh house[/i battering ram, who's job it is to gain yards (nothing like a good stat, to keep bores interested).

Get some flair back into the game, rather than an English equivalent of American Football, where a laptop is king.

As I said on the Ratboy thread, yesterday, Ratchford must have been bored witless, watching that. 18th man, while Ratboy's (and Williams' ) aimless kicks were permanently going the throats of the Kiwi's back 3. Duller than watching a 6 year old repeat of a qualifying weekend of the X-Factor .

Tony Clubb winger/centre to prop.

Very much with your sentiments on this.
Our game does lack flair and we don't seem to have created a top class half-back for years. All supporters complain about their half-backs lack of flair. But defences are so much better and the best defensive team (Wigan) win the big prize. Their games are a grind. Even the great Alex Murphy might find it harder to create. Unfortunately I'm not optimistic for a sudden change of direction.
I mustn't be too miserable ... well done Wire.

Benny Westwood Winger/Centre/Second Row/Prop

Specialists in their positions are getting rarer.

Especially at centre and stand off.

I don't think there are any specialists anymore, other than perhaps goal kickers.

Hooker, who should now be renamed “dummy half” and be done with.