I was disappointed Dexter didn't choose Gina. My reasoning is simple. She is a horrid person. He is too. Maybe they can hold hands and trip along the Highway To Hell when it's all over.

He would never have chosen Gina - she has for the most part had his back for the whole series.
Gina deserves her place in the final. I don't like her anymore either but she's been entertaining since the moment she walked down the stairs.