I’m not so sanguine on “balancing” a GOP ticket by putting a doctrinaire liberal in there. That is defeatism or punch pulling.
I’m thinking of Trump-Cruz and it might make sense just because Trump is goonish enough to provide covering fire for Cruz, while willing enough to learn that he would temper down some of his excesses. Though I freely confess that is just HTRN’s surmise.
I'm not suggesting a doctrinaire liberal like Pataki, or even a squishy compassionate conservative like Kasich. But someone at least overall conservative who could work with Cruz and bring something to the ticket to help win the election.