Steven Seagal: He is a 7th Dan Aikido master. If this was a street fight Seagal would destroy pretty much every MMA fighter who comes anywhere near him.
The fact is with Aikido as soon as any force it placed in Seagals direction he'll just use it to throw you off balace, fling you to one side or break you. The fact is most fighters would not be fast enough to get within his face without ending up severely injured.
Seagal is one of the finest martial artists of our time and one shouldn't take him lightly. He is also a pretty big guy at well over 6 foot with great skill having taught hundreds if not thousands of people.
Do not lump him into MMA, which I love, because it is not the right scene to judge a fighter of his caliber if you're making rules against him. In a no rules street fight he would simply be lethal. He would not fight for any type of decision he would simply incapacitate his opponent.