I loved that Karen finally gets a main role in an episode and shows more development in the character, also I love some of the relations of her common day life as a single mother to that Luigi is facing.
However, in this episode Mario's character development was thrown out in order to fit the trama, making a more immature Mario than the one we commonly follow.
And this whole Luigi knowing how to step up to Mario seems like a highly repeated trama in the series, we have already seen Luigi step up or even taking the leading role, but in the video this was reversed and Luigi was once again teached how to deal with Mario like if he had never done it before.
Outside of the Karen development as a character everything else was a repeat and Mario at its worst.