I think you need to stop looking at this as an E3 conference, as if all that matters is that particular presentation. The idea of this was born from wanting to communicate more with fans, and also allowing them more of a look behind the scenes of the development of some of their favourite titles, past and present. There's been a lot of evolution for this idea, but whatever the case, it ultimately ended up here and it's less about hyping up a particular presentation, and more about the entire experience. This is a pretty huge event all things considered.
I can't speak for individual panels, but there is going to be some great stuff for people attending this event, and a lot of efforts are also being made to show and give more information to those who aren't able to attend. It's very much a celebration of Playstation, but it's also about showing much more than that. Folks get a chance to look behind the development of some older titles, other ways in which certain parts of the game development process work, meet developers, take part in contests, get collectables, and of course, play games. It's being promoted as a community event, because that's what the idea was born from, something for fans.
Yes it's great if you're shown The Last Guardian or whatever, but try to think beyond that too. It's not often you get a chance to pick the brains of the people involved with so many of these franchises, and also get a chance to hear them speak about what made it happen. Who knows, maybe you'll come away with a few experiences worth remembering.