This is why you don't have a half All-Stars/half Newbies season...
It is clear from this season that the newbies were overmatched versus the All-Stars. So I don't think they will ever do this again.
Personally, I loved the first All-Star edition, and wanted a season where they did All-Stars again. But as a Survivor fan as well, I wonder if there's the same internal politics. Even though Survivor is having another All-Star season coming up, my understanding is historically there have been many people running Survivor who don't like it, even though the fans usually love watching the All-Star seasons. So as a "compromise," they bring popular players back (one season was 50/50), but go with the newbies.
So that's a long-winded explanation on what I think happened on Top Chef. There were some people who wanted an All-Star edition again, and some who didn't. So this season they compromised with half and half, and look what happened.
Personally, I love having the alumni come back every so often to play, so I would have preferred an entire All-Star cast this season.