Frank skinners character was very likeable and would be a different dynamic to a companion than what we've had for a while, being a middle aged man not from earth. To add Osgood into that mix would give the balance of still having a female companion whilst also providing a female companion who is, again, different to the kind of companion we are used to traveling with. In summary, although it is unlikely, I think it would be a fantastic idea.
Why do they never think to do something different when coming up with the companion's personality? I know rose, martha, donna amy and clara all have there own personalities, but they are all still of a certain type. I'd welcome a geek like osgood, or a male mate like frank skinners character any day as a refreshing change.
Oh well, at least those characters got to each be in one good story. (osgoods was day of the doctor)