Originally posted by Spiderman
Black Lotus definitely "breaks the scene"; that's why it's restricted.
I don't think it does at all. It's a staple and very potent mana acceleration. But it has always been there for one thing, and any deck can use it for another. That is precisely why I used it as an example (it is one of the most powerful cards in the game, certainly, but it is a staple rather than a card that could potentially be breaking any scenes).
As for your other points...
I agree that there is more to this than Vintage. And there are some important things about this. Firstly, cards that are not considered to be broken in Vintage can be broken elsewhere (much along the lines of what Ferret was talking about with the wishes). Also, cards that are powerful in Vintage are not necessarily as amazing in other formats. While we're still talking about wishes, Burning Wish is restricted in Vintage because of its power (as I've already stated) but it has never been banned in any other formats as far as I know. A card that is broken in one format might be totally substandard in another.
The same goes for Skullclamp (which is banned in other formats, not restricted). I know (well, I have a reasonable degree of certainty) that Skullclamp has never come close to restriction because I follow Vintage somewhat. It has been used in Vintage Affinity decks, but those decks were never a problem for the format.
Necropotence was indeed too good in Vintage, but notice that I said, "...to the extent that you are either playing it or playing against it..." I don't think this was quite the case back then. Now, if Necro were unrestricted in today's environment, it would be, but Necro seems to have a pretty stable position on the restricted list.
Donate/Illusions? Those cards are still perfectly legal and no one even touches them. The only time that they were good was with the aformentioned Necro...
And Academy was indeed such a case. I don't really know why the restrictions against that deck were not made earlier. But I don't believe that one time in the 10 or so years of "Type I" Magic contradicts my statement (three times wouldn't be so huge either).
I am not clear on the meaning of your last sentence, as we aren't arguing the criteria for restrictions or which cards should be restricted (unless I've given the impression that I think some particular card should be restricted/unrestricted, which was not my intent).