First, No they didn't change a rule that if a player flops its a Tech. Its been in there for a long time under Faking.
Second, coaches complain that officials call too much tic tac fouls and don't let them play. Block/Charge is the toughest call to make, I agree. There are situations where fouls can interupt the flow of a game. Like the ones where a defender tries to take a charge the offensive player tries to avoid contact. Which by doing so, almost everytime puts the offensive guy at a disadvantage. So, with that said, if there is contact with the offensive guy trying to avoid the charge and him at a disadvantage, it is a no call.