I feel the show is at it's best when the drama is about the show and not the home lives of the characters. I think that's why 'Dev' is 'gone' and why the love triangle of Julia/Tom/Michael will be over, as well.
As for Ellis, I think they eliminated the character because they didn't know what to do with him. He's too much of a neophyte to the production side to do a lot of damage and they made the character unlikeable as he seemed too sneaky. They never made him someone you wanted to root for since he always had an agenda. Bad writing.... I didn't hate him, but his most likeable moment was in the Bollywood number when he snatched the jewels. If they had made him more of a confidante to Eileen or Tom, the character might've had more longevity.
BTW, congratulations to Christian 'Tom' Borle on his Tony award for his role in Peter and the Starcatchers.
New showrunner next year - used to be in charge of Gossip Girl. Not sure if that'll be good or bad since GG has steadily declined with each season.