Probably just to prevent the people who actually cared about the project from running riot. They put it into development hell because it wasn't finished in time or something.
The issue of Starcraft Ghost irritates me on various levels. Firstly, it's the fact that Blizzard dropped a really good and fresh concept. Secondly, it's the fact that they denied that it was completely dropped, when it clearly seemed that they had no intention of finishing it in the future, and thirdly, it's the fact that they've dropped it and then tried to "apologise" in some sort of way by putting the characters into little side missions and relatively unimportant modding tools in favour of the Big 3 (RTS, RPG, and MMO) they've adopted.
And whatever side-missions with Nova they *have* put into Starcraft 2 I have absolutely zero enthusiasm for because unless it plays like Starcraft Ghost it's just another RTS level. I was enthusiastic for Ghost because it wasn't just another RTS level, it was a third-person shooter title with stealth, elements which weren't completely chartered back in 2001. The developers had a chance to explore something new and more immersive for players, but pulled out when it would have worked. And that I suppose is the biggest tragedy about all this shit-in-a-franchise-box.
And I am VERY unenthusiastic about the novels and comics that they've released.