I think that Splatterhouse 2010 killed all hope for a conclusion to its story. People clamored for years for a new SH and while I was personally very pleased overall; the general reception was so abysmal that I have doubt about ever seeing another one. Namco abondoning the game shortly before its release didn't help any either though.

Another series I think that is dead is Golden Axe. Not that it had much life left in it but Beast Rider sealed its fate. As an aside; its interesting that a significant portion of this thread is in relation to games that have Sega somewhere in the details no?