When you could play a "dad&son" computer game - what would you like about it?

Okay, let me explain: I know a few adult games (visual novels or text based) which have a dad & son theme (you can find the list here on f95zone). For longer now I think about creating my own game but I'm having trouble deciding how the game should work:
  1.  As a player: would you prefer to play as the dad or the son?
  2.  Would you rather like a "straight to the point" game (just dad & son having fun and you decide what they do) or more story-telling (like how son seduces dad and you as a player make choices how to seduce dad)

Feel free to add your thoughts in the comments. I'm eager to learn what your thougts are about such a game.