You could tell he was not satisfied with how his character was shoved in the background by Season 3. He put such a brave front mentioning the Duffer brothers in high regards, but you could hear his disappointment with the Lucas character.
The Duffer brothers wrote Finn Wolfhard's character really bad this season. I know he is a teenager, but come on. Have an ounce of sympathy, writers. I just hope the reboot of Ghostbusters will be good, but I am looking forward to Paul Rudd.