Unless we were to meet up with other characters that, in the PC's history, we have met up with before, our backstory and heritage shouldn't be forced upon us by playing through our childhood in the beginning. Since, in Fallout, the goal was to meet up with your father, it was important that a relationship be made, and thus important to see him as the PC's sole nurturer.
I wanted to say exactly this.
Fallout 3 did it because the character's father was deeply rooted in the story of the game. It would make sense in Skyrim if, for whatever reason, they decided to make a parent a major character. But I just can't see this
ever happening. For a start, there are 10 races, which would make it logistically difficult and also lessen the impact such a character might have on the story. Secondly, it's a series tradition that the player character's backstory is never elaborated upon simply because the series relies on the player character to initially be a stanger and a nobody.
I personally wouldn't like to see it anyway. I liked it in Fallout 3. I thought it was a clever tutorial, but I was glad they just got straight to the point in New Vegas.