The star system was a bland/dull way of going about using the force but it was there primarily to allow the gamer to pick what force skill he/she wanted then allocate a certain amount of power/skill to it. Allowing the gamer to get back into the action but make them feel as if they have been rewarded in some way.
Given the movies and expanded universe in star wars id say the force should be more complicated but that would distrupt the flow of the game.
As for force-push it would be interesting to see real world physics incorperated into the game, (eg, pushing someone with enough force would topple them over and make them drop their weapon).
As for the "shoving thru walls" that would take large amounts of power to push someone through durasteel