I know you were trying to say "it didn't offer graphic card pushing 3d like AAA games but it did X uniquely" but by no means can you call that mediocre, specially if you've ever seen old games.
Gameplay over one specific style of graphics, is probably the concept you're looking for.
And never seen old games? I grew up on Atari. I’ve been playing games since. Even made a few. Fez was amazing but not for its art. It was flat. I still enjoyed it. I think gamers shouldn’t get so hung up on pushing their systems to the limits and instead should focus on pushing their play to the limit.
There's much better games out there is, again, unspecific and bad criticism. There's also a lot of focus on the individual developer (and his personality). I don't care how it's made, criticize it on it's own terms.
I've played many old games. You don't make a coherent or specific point.
I agree with you that gameplay beats everything (I said it in my original comment) and there's no one size fits all, but that's why it's so absurd for you to attack art of a game as mediocre with absolutely no basis. Basically you're trying to use it as a binary opposite of "outstanding".
Maybe pick the words you use carefully or have an actual argument to back then up.