Let's consider the situations below:
We do know that "one" is a pronoun, but what does it refer to in the first sentences?
according to the post you linked I guess it refers to a point, a trick, use or something along those lines. Let's rewrite the sentences without one now:
that's a very good point to know. (similarly - that's a good trick to know)
now which of the sentences you mentioned sounds "More appreciative" (to put it in your words)
that's very a good point/one to know
here, one refers to point or use. and "that" refers to that explanation which was given in the article you mentioned. Therefore, this means: "the explanation in the article is a good explanation" or alternatively, "the point in the article is a good point" as you can see for yourself it reads awkwardly since we're repeating the same words twice. hence the reason why we use pronouns instead of repeating the word!
that's good to know
here though, "that" refers to the explanation or point that was mentioned in the article you linked, this essentially means, "the explanation was good"
so as you can see there is virtually little difference in meaning or strength between the two.
in other words, if you elide "very" from the first one, sentence 1 and 2 essentially convey the same level of "appreciation", meaning the element that makes sentence 1 sound more "appreciative" is "very", and it has nothing to do with "one", a measly pronoun!