Old blades are easy to setup. I can have one setup and running in under 5 minutes and then you don't ever have to touch it again :p
Yes, but for people (like me) that want a laptop sitting in the garage of an older house running multiple miners via WiFi, USB is actually a godsend.
I also think they will sell like hotcakes to 'noobs' because of this fact. Look at the premium BFL miners sell for on eBay vs. blades.