If the court case is done and there are no appeals in progress... I'd like to take a look at the public records regarding this case.
As far as I know, neither guy seems to be in the right here. Greg Hastings did effectively abandon his franchise as he didn't make another game until Activision wanted to, he still would have gotten royalties by using his name - if I'm not mistaken - and all he'd have to do is sit on his butt doing nothing.
Activision's tone, however, leads me to believe that they found a means to paying him less royalties and just owning the license of the franchise in its entirety. Which isn't so odd considering EA Sports, but if Greg Hastings had the rights to said franchise they certainly wanted to pick a fight.
That's my two cents regarding this. Activision saw an opportunity and wanted to take it, that's just business. Greg Hastings was picking his nose and not making a game with his name in it for... five years [http://en.wikipedia.org/wiki/Greg_Hastings_Tournament_Paintball_MAX%27D]. Whereas EA Sports keeps on releasing their sports games once a year, so Activision figured "Why the hell not?" before they were promptly ***** slapped into place. Besides, it seems Activision already released a paintball video game just two years ago. [http://en.wikipedia.org/wiki/NPPL_Championship_Paintball_2009]
I'd hate to take the side of Activision, but if I had to pick the bigger douchebag... it's Greg Hastings for just now wanting to make a game using his name. Again though, I don't know all of the specifics and that's why I'd like to take a look at the public records, if I can find them.