Dez didn't "beat up" anybody. He hit his mother with a baseball cap and pulled her hair, she did not require any medical assistance and (despite Dez's issues) it was the first time he was actually arrested. Doing that to your mother is obviously not the right thing to do, but there are a ton of great NFL players who have done a lot worse. The loveable TV personality Michael Irvin stabbed a guy in the neck with a pair of scissors one time, but nobody seems to remember that.
http://sports.espn.go.com/espn/page2/story?page=pearlman/081016
More importantly you don't know all of the facts involved in this situation.
Maybe Dez's mother is a nutty crackhead (she did spend time in jail for selling crack) and she attacked him while he was arguing with his step brother (which is when the incident occured) and Dez was defending himself. I think if Dez Bryant (6'2 220 beast) "beat up" a frail woman twice his age, she would require some medical attention... Just my opinion.
Now let's compare Bryant to Misi both on and off the field. Off the field Koa Misi was arrested for breaking a guy's face by punching him through a wooden door, while Bryant was arrested during a family skirmish where literally nobody was hurt... Both guys (arguably) made a dick move and they got busted for it, neither situation is the end of the world.
On the field the two players are not even comparable, to me (and most objective eyes) Misi is "Mising". The guy has barely shown the ability to be a fringe NFL starter at either OLB or DE, he doesn't have dynamic pass rush skills, and if he doesn't step up big this year he might not have an NFL job ever again. Dez Bryant, on the other hand has not been GREAT yet nor has he been a model citizen, but the kid is twenty ****ing three years old, and he already has a 928 yard (14.7 YPC) and 9 touchdown season under his belt while he was nursing an injury... Bad hammy I believe but I could be wrong. Just so you know, 9 TDS was tied for 4th in the league amongst receivers last year, the only thing that Misi was 4th best at last year was getting swalled up by offensive tackles, the guy is garbage.
In 2010 we could have stood pat (or traded down a little less) and picked Dez Bryant and Aaron Hernandez, who are both way better than Odrick and Misi. Our offense could potentially be sick right now if we had Bryant and Hernandez. Is Bryant great right now? No, but he could potentially be if he just grows up a little bit and stays healthy. Again, the kid is only 23 and he's flashed huge talent.