World of Starcraft?
A more robust Diablo MMO?
Well, Titan was none of the above. According to an article on Kotaku, Titan was supposed to be a hybrid Sci-Fi shooter with a heavy dose of MMO elements. More than anything else, it was supposed to be similar to the recently released game Destiny*, but with much heavier MMO interplay.
Given that this would have been a completely new property for Blizz, it would have been that fourth leg to their table that currently has Diablo, Starcraft, and Warcraft holding the company together. It does sound very interesting in concept --particularly the ambitious nature of the economic game-- but I know I could never play Titan since it's a shooter.**
In the end, I suppose that Destiny was the final nail in Titan's coffin, since you're getting about 75% of Titan in Destiny's released form, and why would you want to compete with a game you're releasing?
One aspect to Titan that might have been interesting would be how it would have translated into PvP. With MOBAs all the rage these days, could Blizz have turned a portion of Titan's development into a PvP game that would compete with already released MOBAs? I suspect PvP wasn't a focus of Titan's development process, and that might have hampered Titan on release as well.
Regardless, Titan is now dead, deader than Jacob Marley, but you never know when elements of it will appear in other, already released games.
*By Bungie, which is released through Activision/Blizzard.
**Shooters give me headaches. Seriously. I have to take dramamine before I can even attempt to play a shooter.
EtA: Cleared up a grammar error in the first paragraph.