Legally, where does that leave StarCraft, especially the soon to be released Heart of the Swarm (all have units called Space Marines)? If GW don't (and never did) enforce their trademark against Blizzard, do they have any say against a book author that wants to push the topic in front of a court? AFAIK, Blizzard didn't license the term.
It's pretty funny, Warcraft and Starcraft are both blatant ripoffs of GW's Warhammer and WH40k. I even recall reading somewhere the original Warcraft RTS was to be an officially licensed Warhammer game. But gee whiz, I wonder why we don't see legal action brought against Blizzard?
WH original and Warcaft are both simpler - they both rip off LOTR.