Maine and Nebraska already divide their electoral votes.
Michigan doing this would definitely help a little bit, but the math is still on the difficult side. Instead of having to run the table on swing states, this would give the Republican nominee breathing room so that he could afford to lose 1 or 2 of the non-heavyweight swing states.
Although Maine hasn’t split its votes since they started the method in 1972, and Nebraska has done so only once since 1992 (2008, 4-1 McCain, Omaha going to B Hussein).