Well I absolutely would go with a gainline player in the back line.
In a perfect world my preference would be the team i named earlier in the thread: Corbs, Youngs, Cole, Lawes, Launch, Vunipola, Woods, Morgan, Youngs, Ford, May, Burrell, Tuilagi, Roko, Nowell
Out of what's left at the moment i'd look to play a back line of youngs, ford, may, 36, burrell, nowell, Brown.
Tactically i'd kick pretty much everything in our own half, move Halfpenny around and make him get in the air (he's good but not good enough) and then from our 10 on wards i'd be looking to use a midfield contact point from off the top ball to beat the gain line, then as we don't have the close passing game of your NZ etc... i'd be looking to use pick and goes and runners off youngs and ford to keep the welsh in transition.
The point isn't to just run head first into contact, but you use a power runner to hit gaps and suck defenders in and ultimately give your pack a target - Burrell is fantastic as this and once the welsh defence is going backwards and their line speed is shut down i'd look to utilise the wider game hinging off Ford and 36.
I think England got it almost spot on last year, you know who else get it almost perfect?
Saracens & Northampton.