There is no reason to intentionally make contact with another player, except for in the 'Shoulder charge'. That is not to say that there shouldn't be any contact, as in many of the actions in football contact is inevitable. Even in a tackle(sliding or otherwise) should be non-contact; A 'clean' tackle should not touch the other player. Demonstrated by the fact that 'going through' a player to get the ball results in a foul.
You've actually highlighted my point in that the majority of people think of it as a contact sport, and it has evolved that way. I also I agree with you in that football is played that way nowadays. But it shouldn't be. Grabbing, jumping on, pulling back. Excessive use of these tactics get penalised. But why should even the non-excessive versions of the actions be allowed?
Out of curiosity, Where (apart from the shoulder charge) should contact with another player be intentional? Even the act of 'Shielding' isn't intentional, as you are merely protecting the ball. Contact isn't mandatory.