Strange topic... What reason do you need for Panam being nomad? She is just this kind of person, the good thing about LI's in this game is that they are all different from each other.
Panam is a free spirit loving the life outside the cities. Kerry is a media person, who has bonds with a city instead.
Some people complained that you can't take Kerry out of the city, but for me it has a sense, his life is connected to the city as well as Panam's life connected to her nomad family. It's ok that characters have their own personality, which may not fit protagonist all the time.
I think he wanted a female Love Interest that represented the city life/punk more. But I think really there is only one LOve Interest per body/orientation, so they were bound to miss many players preferred types.