Lets bear in mind that its entirely possible that the developers of this game consist of a handful of people with limited resources and can only reach so many customers. That said, a Mac version of this game would be great if it can get done.
As far as game mechanics go, I would like to see some way for less well known candidates have some chance at winning, not necessarily easy but a chance nonetheless. I remember playing as Russ Feingold during the primaries and that was fun, difficult but fun. Then the general election came and I had polling somewhere around 16% and could barely cling to liberal leaning endorsements. I suspect that is semi-unrealistic as almost any democrat can count on support from a handful of states as "base states" i.e. my New York / Mass polling should never be less than 20% especially for someone who isn't insanely far left.
Also it would be interesting to see some introduction of Super-delegates and being able to win them over.