Realistically, very little. But, the check box requires the code to perform a decision, which typically adds to debug time. When it's only ONE decision, it's not likely to be a problem. But, it is, as I said, "a bit more complicated".
However, having a check box (or, other decision-making construct) does allow for freedom among players, which was one of the bigger objections. So, it seems like a good addition to me.
At LAST! The greatest campaign board game of all time is finally available for the PC. Can my old heart stand the strain?