First of all, currently there is no concrete evidence that Doug Walker left Channel Awesome (however, if any sort of verifiable source backs this up, I will delete this opening sentence).
With that being said, I do have several things to say about the issue.
First of all, this is not a new thing. It's only perceieved as such because of how things escalated after Not So Awesome, but the issues have been present since "To Boldly Flee". Keep in mind that Spoony, the one that was at that moment the more outspoken about how Mike Michaud screwed him, never added his experiences to Not So Awesome.
Second...Channel Awesome these past years only existed for show. Ever since blip went down, every single major contributor went back to youtube, making the Channel Awesome site (and, as a result, Channel Awesome as a corporation) pointless. Keep in mind that the greater talent (Nostalgia Chick, Marzgurl, Phelous, Lupa, Spoony) had long since left the site when the Controversy erupted.
I'm wondering what's James (James Rolfe, the Angry Video Game Nerd) take on all of this, considering his longstanding support of Channel Awesome and with friendship with Doug.
I do believe some of that bitterness is starting to come across in newer videos. In "Jeepers Creepers 3", phelous kept taking potshots at Victor Salva (another filmmaker who abused his crew), and the newest Linkara video is a review of the Terra arc of the original "Teen Titans" TV show (where a seemingly friendly and charming member of the team betrays said team and flip flops between sincere regret and outright malice).
And there's something that isn't taken into account in all of this...the "Demo Reel" leftovers. They are not reviewers, they are actors. The end of Nostalgia Critic's run on Channel Awesome means Tamara, Malcolm, Walter, Heather and the rest lose their jobs. That's why Malcolm and Tamara were so defensive of Michaud and of the infamous "facts vs accusations" response...their jobs were on the line.
In the end, I do think Michaud's actions are reprephensible, and I do wish the best for all the reviewers. But as I said before, after the blip shutdown, Channel Awesome existed just for show, so I don't really see what's happening as any meaningful change. Rather, it's what should have happen immediateloy after everyone moved back to youtube.
After the blip shutdown, they were just delaying the inevitable, and now they can't afford to delay it any further.