Why would defence be an issue with Maker at C? From all reports that is his calling card, and what Milwaukee drafted him for. He's incredibly long and athletic, exactly what you want from a five man. He may not have the smarts of a Bogut, but he could have the length and athletic ability to protect the paint like Gobert. I'm sure by 2020 he'll have gained weight and gotten stronger too, particularly if he's still in the NBA.Given Simmons ability as a rebounder he can help out a lot though, could get away with it a bit. Also need a C that can stretch the floor if playing Simmons because his current lack of shooting means it gets very cramped if have two non-shooting bigs there. Clear out the opposing big defender though and Simmons should be able to get to the rim at will and if defences collapse on him hit the shooters in Mills, Delly, Exum/Ingles, and Thon. Would be nice.
Defence is the issue though with Thon at C.