The problem is very few of the better English players would be willing to take big pay cuts to go to the NRL. Ellis did. Burgess would almost certainly have been able to get more if he'd stayed.
Eastmond and Tomkins, neither of whom have anything like complete games, will probably be on big money from now on - certainly far more than any NRL club in its right mind would pay. McGuire's probably a good case study of their likely futures. Ignore what fans of Sts and Wigan may say, the chances are that if they stay in England they'll still have the obvious, ridiculous gaps in their games in 5 years time. McGuire looked better than either of them when he first played for GB, yet he has simply not developed the all-round skills he should have by now.
Getting more English players to Australia would do England the world of good, but its hard to see many going because of the money. In that case the best we can hope for is getting them to go to the NRL as juniors for a year and improve them at the key 16-18 age.