#2 is not a trend we want to start in industry. With phone screens, both sides make an investment. With a pre-screened assignment, there is very little cost to the company. This gives them a much stronger incentive to throw everything on the wall and see what sticks. Or even feel that they're doing candidates a favor by 'letting' them take the 4hr assignment. Doing a phone screen aligns incentives.

You think you hate whiteboard interviews? Imagine having to to 15+ different take home assignments for different companies before you even get a chance to talk to a person.