Okay, now I'm neither a lawyer nor an accountant, but I'm pretty sure that "$12 of the profits" isn't what the contract specified. You might want to fix that typo. Also the one about WOW's fanbase "waining", since that's not a verb.
Starcraft Ghost... man, I remember hearing about that back when it was first announced. I remember a discussion, a few years later, where someone posted a picture of the statue of Nova that Blizzard had built, and someone saying "look at the detail in that butt! Just imagine what those graphics will be like!", and thinking that some people can't even do lechery right.
Anyway, two more that no one's mentioned:
Star Control 4 (or, later, "Starcon", since stupid naming conventions aren't exclusive to this century). After a disappointing third installment, Accolade was all set to return to form- or to branch the series off in a new direction, or possibly do something else altogether. A lot of what was leaked contradicted other stuff that was leaked. Still, all that potential, blown to hell. And then, a decade and a half later, the rights to make a new Star Control game wind up with Stardock, of all companies. And the head writer is a guy from Cracked. I'm... less than optimistic about it.
The bigger one, however, is Babylon 5: Into The Fire. This was months away from release when Sierra canceled it. It looked damn cool, and if the thought of flying a Starfury into a battle doesn't send a tingle down your spine, then haven't seen a Starfury in action lately. And that's the kicker: it was 1999. The series had just ended the previous year- and I mean just that; it wasn't canceled, it ended, which is very rare, at least in American television- and Crusade not being what it should've been (and getting canceled before its first episode aired, which I do believe is some kind of record), it could've buoyed interest in the series and let us get more from the universe. Remember all those other Babylon 5 games? No, of course not; there weren't any. (Though there was a surprisingly long-lasting tabletop wargame, which eventually saw a public spinoff release with a stupid amount of conversions; ever wonder who'd win in a fight between a fully loaded Sathanas superjuggernaut and six Borg cubes? I can tell you.) But Into the Fire got canceled, Sierra went bust, and so we got no games at all (until the Hard Light people got up and did it themselves, but still, what could have been...).