It wasn't your mention of the demo that made be buy the game. It was a coworker that had bought and was enjoying it.
And I have to admit, I enjoyed it. But having finished it, I have no further desire to play with the game what so ever. I probably wouldn't even buy an expansion pack unless it was cheap.
Diablo II on the other hand was good enough I played three different characters from start to finish, and took one through again at the second level of difficulty. And having finished Dungeon Siege, I'm hungry to go back and play Diablo II some more.
From the little I know of how the game design evolved, it does look like it was massivly cut back. The early comments I saw about the game where almost positioning it against Neverwinter Nights more then Diablo II.
Hopefully they will do a Dungeon Siege II, with the same graphics engine and a rewritten game to back it.
Jay