He has no power now. He cant vote in witnesses and he cant token swap. If he had control over the top 20 witnesses then he might have been able to dismantle Steem (which was his original idea), retain exchanges and move Steem to Tron. 

Now he cant do nothing. 

My only fear is that witnesses let up and trust him on his word. 

We need to remember that ITS HIS PROBLEM that he bought tainted stake, not ours. 
He should have done his research..