This is true, if their was an agreement there would be a rightful suit, HOWEVER, Level 1 would not be the target, because they didn't sign anything with WME, it would be against Warren Miller.
I know you can't own someone's legal name, so there's no legal issue there, you CAN own someone's likeness, but that doesn't include their voice, it includes their fictional character - key word fictional, however he is not a fictional man, so that doesn't seem likely. So I don't see where WME can have any legal stranglehold on Warren Miller or Level 1.