Nice response, Fidgety. I think your criteria hold up much better than mine. Mine were written off the top of my head, and maybe serve better as criteria for review (if even that) than criticism.
Looking at poetry, most people find it impenetrable and impossible to enjoy.
I would say that although this is true-ish, people can certainly be taught
to enjoy poetry (though it really needs to be done one-on-one) by pointing out ambiguities in the text and showing how it can have several meanings etc. However, and I think this applies to any criticism including games, even when people have the tools to enable a deeper reading, they just can't be bothered. The reward possibly isn't worth the effort. For example, I used to read poetry, but don't any more. It doesn't interest me. The will has to be there to seek something more, and it just isn't there for most of us. I think this idea has been addressed on this site before where Chi has said, people just aren't interested in criticism, by and large. It's a case of won't rather than can't.
None of which is relevant to the argument at hand. I like your points. I guess that the main issue I would have is that everyone can define Ambiguity or Tension in different terms where games are concerned, with the huge differences between genres, and the subjective tastes of gamers (eg preferring Platformers over RPGs, or Shooters over Strategy games) muddy the waters still further.
I'm currently only able to perceive Ambiguity as part of the narrative in games - for example the difference between what a character says, and what a character does. I think this may be the starting point for a lot of people who, once they notice this, then start questioning why the character behaves like that, and thus uses that as an entry point for further analysis\criticism. But I accept that this may be a simple version of your point about the difference between intention and action.
But yeah, good points and well made.