I feel sorry for April in a way, i mean she's caught up in the situation. She never did anything to make things harder on Luke, Anna or Lorelai, if anything she made Luke realise that Lorelai could be part of her life (with the birthday party).
I just hope Luke realises this, especially when Lorelai told luke that Anna had said that when they were married it would be fine. But then again he is a guy and guys always find ways to complicate things