The only showcase I am really excited to watch is Nintendo's. They can pack a lot into 40-50 minutes. There are always new games announced, and often the new announcements are for games that are just a few months away. That is the way to do one of these showcases.
However, I will probably watch most of the others except the VR one. With the other presentations, I hope to be pleasantly surprised while usually making fun of them when they suck like I expect. Either way I am entertained.