I don't see a Digg like exodus happening yet. I recall leaving Digg and thinking with the new version that these guys were taking the piss and completely out of touch with users.
Reddit hasn't gone quite that far but it definitely used to pride itself being a free speech platform and thats changed now - locking sub reddits is restricting ideas and behaviour despite what the admins say. You're only even in favor of free speech so long as you tolerate things that are mean, awful and sometimes even hateful. The bans, firing and lack of communications weren't a good idea and didn't result in a "safer" reddit.
I don't think Ellen Pao is the right person to run Reddit. I think Reddit is facing the same dilemma the music industry faced when they realised that their best customers were also the ones to pirate the most music.