Basically, the value proposition seems to be something like Groupon. Humble Bundle will become a place known to offer low priced games. People will go there in order to find low priced games. The fact that so many people go there will attract game developers to offer their games there at a huge discount hoping to get their name out and get some traction. I am not sure it will work but I am pretty sure this is their plan.
Do you think "low-priced" is a necessary part of the offering? I'd be strongly tempted to emphasize the other parts (aesthetic, Rage Against The Machine, etc), deemphasize "pay however little you think is fair", and walk up the number of sales in the $40+ bucket.
Humble Bundle is becoming the go-to place for platform agnostic independent game sales. Imagine what would happen if Humble Bundle, Inc. became the defacto, cross-platform Steam competitor. On top of that, Jeffrey Rosen's connection into the gaming industry puts him one step ahead of any potential competitors.