Why "good thing"

> I'm going to need someone to point out why moving from "invented first" to "filed first" is a good thing?

I think that it's because it makes the system more predictable, even if less "fair". CEOs love predictable much more than fair.

As to prior art, it is my understanding (IANAL) that you will still be able to successfully argue that other people where doing it long ago, and have the patent invalidated. What you won't be able to do is to come with evidence that you've invented the same thing a month earlier than they and seize their patent to yourself on that grounds.