This is a bloody good topic, but I always feel that these topics drift into long, almost endless threads were nobody actually reads the previous 'umpteen' posts because it's a lot of time wasted.
I agree with a lot of your points but I could never place it like you could. That's not exactly a clear way of putting it, but basically I've never understood why I've loved a game enough to stand by it even when other die hard gamers are tearing it to pieces.
It's never down to instant likeness for me, Some of my favourite games of all time I've played for bugger all time, almost forgetting about them until I go back to them and finally get to know their true worth.
Other than that, it's go to be special, I never find a game that seems very familiar to be a good game, not unless I really liked the prequel (I know that sounds weird, but I don't like copies of games when the people didn't make the original)
Other than that it's genuine innovation to be honest. Some of the finest games I've played recently have been clearly brilliant because of the risks taken in making something new, something inovative