They added more heat sinks to the VRM's thank god. That was the main problem with the B350M models, the VRM overheated easily with the 8 core especially, forcing the Asus TUF micro atx as the only option.
@ AlistairAB
I've got the Asus TUF B350M-Plus mATX, and it needs a heatsink on the memory (mosfets) too, not just the CPU. I see Gigabyte too still leaves those off on all but the flagship board. My other B350 AM4 board the Asrock AB350M Pro4 at least has both. I wish that little item were more common.