1) My understanding is that Steve Long was the original force behind Champions. The HERO System is his work and Champions is a subset of that system. Here's an excerpt from the hero system page:
"And now I’m back to full-time writing on Champions for 6E [6th edition of the HERO System Core Rules]. As of this writing, I’m deep in the middle of Chapter Two and making good progress."
2) I recommend purchasing the downloadable versions of this system, but I suspect you can also get the hard copies shipped wherever you need them. Here's the shopping page:
https://www.herogames.com/browse.htm
3) After trying WoW, I doubt I'll ever touch another MMO, even if it was inpspired by such a great RPG system.
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It's ironic that I originally found this system as a result of a post on these (Dominions 3) forums.