Thanks for the link Thor, I added it to my bookmarks.
If a publisher can reboot X-COM, is that the exception or the rule? I think it boils down to communication between publisher and developer. It seems like the developers that have a vision to make a great game and a publisher who isn't forcing a deadline make a compatible team. I could go on for hours about this subject, my favorite being Fallout 2 and the amount of content they originally planned in the final release.
I'm almost tempted to poll people. "What game sequels were better than the original?" There's probably dozens of Youtube videos.