Personally, I think the GOP is crazy (even aside from their policies). For whatever reasons they just don't seem to make decisions based upon electability (nationally, anyway). Rather, their metric for decision making seems to be based on how much froth foams out of the mouths of people in the crowd.
Looking at 2012, for example, I think the most electable option may have been Huntsman, but he didn't even make a dent. Meanwhile 9-9-9 Cain was at one point a frontrunner. In the end of course they went with Romney, but he was a clear loser well before he lost. He never had the demographics right to even have a chance. Why they seemed completely blind to this is beyond me.
At any rate, Martinez would seem to be a great candidate. She has a compelling story, seems to be a pretty solid conservative, and most importantly could do well with women and Hispanics, whose vote is no longer optional. But, unless something happens to the GOP between now and then, it won't ever happen. She doesn't have that brand of crazy necessary to make people foam at the mouth. If you were to go back in time and put her up on stage during the GOP debates, she would have looked like a Democrat.
So, the short answer is that Martinez makes sense, therefore the GOP won't go for it.