You probably shouldn't watch this late on a Wednesday afternoon, mentally exhausted after a long day at the office. But if you're up to the task, here's a video from the NFL demonstrating legal and illegal hits.
Pass-heavy offenses have slowly become the norm in the NFL in recent years, part of the game's natural evolution. Looking at the types of hits demonstrated in this video, it's clear that life is going to get a lot harder for cornerbacks, safeties or any other player defending receivers or attacking quarterbacks. That should translate to an even quicker pace for teams to become more and more reliant on their downfield attack.
The problem with this will lie partially with enforcement because it requires consistency...we're looking at you Ed Holuchi. That's what could really make life hell for defenders, as they try to guess what's a legal hit and what's not.
All the more reason for the St. Louis Rams to make their offense a more aggressive animal under new coordinator Josh McDaniels.