I'm not losing interest. I'm just happy enough right now where I don't have to wait for 2 years to see screenshots of Luigi. (I knew he would be in Brawl, but I wanted to see him in action! Not seeing him was torture for me!)
I'm pretty much happy with anything that is getting confirmed. Characters, stages, items, Assist Trophies, Pokemon… I like just seeing that alone. However, I want to see the more obvious veterans get confirmed already, I would love to see another newcomer, I want to see what modes there are in this game, and I would love to see a new trailer. I actually miss the old DOJO!! because the daily updates got me hyped every single day until release. It's hard to keep my hype on-going every single day when you have pointless screenshots for the Pic of the Day with no explanation (like Marth and Luigi's nose in one pic).
I'm still hyped, but I wasn't as hyped as I was with Brawl.