I can't believe the writers didn't do anything with these two

Yes, I would have liked to see more of them. And considering that season 4 would have been perfect to bring them back or season 5 being the last one, I was very disappointed that they forgot about them. Since after their respective cameos in the Christmas special they didn't appear again. And only Resasuke was mentioned (although without mentioning his name) in the first episode of the second season. From there they only made cameos in the comics and appear in the cell phone game.