Leonard believes four victories would be a huge ask, but he believes England can sew the seeds of a recovery and build a platform for the defence of the trophy he helped claim in Australia in 2003.
He said: "The most important thing for the team and the coaching side of it is to produce some consistency.
"It would be folly if we demand from Andy Robinson and his players four wins out of four because we are playing against two of the best teams in the world.
"I do not think that is going to happen, but we have got to go into those games looking to improve upon what happened in the Six Nations and what happened on the summer tour.
"We have got our players back now because in the summer, a lot of players were rested because of the Lions in 2005, so these are quite exciting times.
"Let's go in, let's play to a game plan, let's try to forge forward with the World Cup in mind and hopefully what we will see is a progressive improvement in every single game.
"Once we have got that, we can be a little bit more confident about looking at the Six Nations, because we want to do well in that as well.
"Then you have got a summer tour and then you have got the World Cup, so it is very, very important for England to not only put in the performances, but also be consistent as well.
"That consistency is not only in the game, it is the players, it is the selection, it is everything.
"After the four games, we will know where we are and we will be able to use that as a platform going forward with the World Cup in mind."
Leonard's comments came as he visited the Billingham Campus School on Teesside to take part in a coaching session with around 60 youngsters as part of a joint RFU and Royal & SunAlliance initiative.
England's most-capped international - Leonard played for his country on 114 occasions - insists Robinson can repeat the feat achieved by Sir Clive Woodward, but knows his team will have to start proving its credentials sooner rather than later.
Asked if England can win the 2007 World Cup, Leonard said: "Yes, England can, I would never write England off.
"The last couple of years have not helped us. We are three years down the line from the World Cup and we are still in a transitional period.
"Once you get through to the quarter-finals, there is an element of luck that comes through in a World Cup and games can turn your way.
"People can go in and out of form, so I would never write England off.
"A lot of hard work has to be put in before that, obviously, but do I think England could do it.
"But first things first, let's have a look and see how the autumn internationals go."