I've just been thinking and came up with a few ideas.
From what I think, every time you offered a player a new contract, they always got more than what they had.
So, what could happen is that you can negotiate contracts. So, a new up and coming youngster who appears to be a real asset could go from £300 to around £800. Then the older players in the team, around 30+ could take reductions, along the lines of FM or something.
Also, the older players could retire and possibly join the coaching team etc
Have the game sign other players as well, so once you sell a player who is world class, another team in SL would come in for him, rather than see him go to Widnes or Doncaster ...
If possible, could the game go on forever, rather than just 7 seasons?
There could be a WCC each season, and once established as a coach, be able to apply for a National job.
Another thing, although it seems really petty, have it so that the fixtures are randomised each season.
They are all I can remember, for now