That is exactly what I wanted you to say.
If we conclude that the narrative of Legacy can be told without the gameplay, Legacy is a potential valid source. I say "potential" because we haven't proven its validity; we will only have disproven one of the many arguments against it.
And yet there's one thing that hasn't been considered in the past few posts: this isn't a Legacy thread! Shambala's proposal in #23 of this thread was to discuss each game separately, so we should leave Legacy be until we determine the status of the medium as a whole.