Butkus was a mean SOB, but his style of play would never be allowed in today's NFL. He would get thrown out of every game for spearing, helmet-to-helmet contact, and unsportsman-like conduct.
There are some guys that would play like that today if they were allowed. A prime example is James Harrison. In the Super Bowl, he held an offensive lineman on the ground and drove his elbow into him. When the guy tried to get up, Harrison punished him back to the ground and stood over him, daring him to try to stand up.
All of the people who like to praise Butkus cried and whined and called him a poor sport (including the announcing team). Harrison is a throwback and probably the closest thing to Lambert and Butkus that we have in the NFL today... He is mean, nasty, and just doesn't give a f#ck.
Still... I don't think that special-teamers get enough attention. That is the most dangerous thing to do... Possibly in all of professional sports. Steve Tasker was the greatest gunner of all-time. He was literally the definition of a 'wrecking ball,' as he would single-handedly destroy a team's return unit by crashing into their wedge.
Watch this video and prepare to be blown away. The guy was a maniac.