They're getting a free shot from 12 yards in a 6ft goal. It's already hard. The idea of stepping off the line stacks an unfair advantage to the player about to get a ball blasted at him is stupid IMO.
Of course players should be able to block shot or crosses with their arms. Most players don't...it's usually leathered at them from 2 yards, they're not even looking at it, they're sliding/running... basically doing anything to not stop a ball with their arms.
And no, these aren't laws that weren't enforced. They're laws that are now being re-interpreted, calculated, measured, reviewed, zoomed in, frame jumped, and replayed in as many speeds as you want. This additionally doesn't provide consistency either.