I think Bitadze is to Zizic as Morant is to Sexton. They're not really good fits together. But just as Morant has some elements to his game that will probably make him better than Sexton (most importantly, his passing ability), Bitadze has some elements of his game that will probably make him better than Zizic (3-point shooting, shot blocking).
I decided to count Bitadze as a "good fit" since I don't think we're really all that invested in Zizic anyway...we could probably move him for a late first or use him as sweetener in a larger trade fairly easily, while trading Sexton would obviously be an enormous undertaking where it might be very difficult to find a good trade partner and get our money's worth. Of course, we could also simply keep Zizic as Bitadze's backup.