Meanwhile, as Gatland revealed his squad he questioned how England could leave out quality players like Luther Burrell and Dylan Hartley and still bring enough heat from the bench.
"England have the problem of which way they want to play and who they want to play, who at nine and 10, who they play in midfield and the make-up of the back row," he said.
"It seems to be that they need Geoff Parling to call the line-outs because he is their go-to man there, but who is his partner and who comes off the bench?
"So I think we are a little bit more settled and more comfortable with the experience we have got and the combinations we have got. They have some world-class players and a depth I would love to have but they are probably not 100 per cent sure of where they are going."
England host Wales at Twickenham on September 27, three days after Smith's tournament picks, the Wallabies and Fiji meet at Cardiff.
Gatland has been forced to alter his RWC squad to help cover for players carrying injury. Locks Alun Wyn-Jones and Luke Charteris are banged up and captain Sam Warburton feared his tournament was over when he damaged a shoulder at a training camp.
"I remember taking my T-shirt off and not being able to lift my arm," Warburton said. "For a good couple of days I was panicking. You think the worst, but luckily within two or three days it had recovered."