You are asking the wrong question. If a substantial number of districts are designed to be polarized, then those districts representation will also act in a heavily partisan manner, which can create and perpetuate partisan gridlock. This in turn can have a deleterious effect on the principle of democratic accountability. Essentially we are talking about gerrymandering. If one political party designs it to their advantage, they can negate the votes of many, even to the point of changing election results.