I dug into Tillman's stats from the last game. He played a total of 15 minutes, of which about 2 of those minutes were garbage time with scrubs. Of the 13 minutes of actual rotation play, he had about 11 with Horford (+18) and 2 as the 1 big (-6).
I did not see the whole game but these stats highlight what I liked about his play during the parts I did see. He was great as the 3rd big with Horford. If this continues, or even gets better, that gives us a legitimate 3 big rotation. Kornet can be used as he should be used, as a 3rd string big, and Brissett can fill in as a swing/big as needed.
I still don't feel like I have seen enough of Tillman to be sure what he really is as a player. He is still a poor FT shooter so that is a vulnerability. But he showed last night vs. DAL that he can really impact the game just doing all the "blue collar" things. That kind of frees up Horford to play his game.
I am really encouraged about Tillman now.