well I'd go for a balanced team, but I am sure not everyone will agree with that.
But even if you have a star player the odds that he gets injured just before the playoffs are not that great!
Part of being a good manager is dealing with the uncertainly of injuries etc. You try to build a balanced team, a team with some depth and a mixture of players that can fill in at multiple positions.
Over time, the random events will even out and the better managers will rise to the top...
Steve