Kick grants a free hit, nudge does not. Defense nudge with shield and polearm works great for facehuggers. It's easy to sandwich a foe between you and another enemy (if an obstacle's nearby) and try to kick him to get an extra hit for yourself. Nudge in a group fight is typically for stopping his attack and allow for a teammate to get a hit in.
Not sure where the disconnect is.
I'm making an alt with full strength that uses a long maul just for the ability to nudge people off high places to watch them fall and splat on the floor below.
