(1) Regarding the article: boo f-ing hoo.
(2) Why Rails 3.1 actually is blowing it: There is no way to turn off concatenation of js/css files in development! WTF? Have these guys ever developed a client heavy app before? That is a total non-starter. I love how the entire goal was to make js a first class rails citizen but you can only debug these files in firebug as one giant file! What a f-up!
That is great news! Rails 3.1 otherwise has many great features.
However, I'll be honest, I find it completely unbelievable that you don't have a problem debugging in one huge js file. I guess when using coffee script the connection between what you are debugging and what you are editing is already completely severed so maybe at that point it doesn't matter anymore.
I find that I like debugging the concatenated version of javascript better. I end up using search a lot more in chrome development tools but I actually get to the place in the code I want to get to faster with one file and search.