Interesting choices. To give England the best chance of winning the RWC, my picks would be:
Johnny Sexton - losing him would make England clear favourites against Ireland ignoring the positive impact he would have on England. Plus it would put an end to the Farrell vs Ford debate!
Richie McCaw - New Zealand (potential final opponents) lose their talisman, England gain a world class traditional seven.
Kieran Read - a strange choice I know given England's relative strength in the position although Read still walks into the starting jersey, but I couldn't resist the idea of ripping off two of New Zealand's starting back row.
I was also tempted by Dane Coles because of how poorly New Zealand cover him and Aaron Smith for his sheer class in a position where England are average at best.
Before anyone accuses me of typical English arrogance, I'm not assuming that England will win the Pool A, just saying that these choices would give England the best chance of winning the whole shooting match (poor job of explaining what I'm getting at I know).