Some players don't buy there tokens so therefore cannot constantly afford to buy new players. It could be beneficial to introduce a loan list whereby players who are "Not needed" at one club can be loaned out for a period of games (i.e. 3 games) to cover any injuries etc. this could be for a small fee which is given to the "Parent Club"/club loaning the player out.
This would give the game an extra dimension and probably help to keep many managers interested. I know 1 of my friends has had horrendous injury problems of late to the point he could only just about field a starting XI.
To facilitate this addition it would be preferable to also expand on the squad sizes as it can isn't realistic to cap the squad size at 22 players.