It would only work, however, for games which use our interface library to save high scores on our systems. If a game manages its own high score system or posts the scores elsewhere on the Internet ("in the cloud") then we won't be able to post those scores on our site.
Even if the site could only keep track of highscores for users that use your interface library, I still think it would be cool to have. But, then again it would probably cause a lot of users to say, "All my high scores aren't listing in my 'my high scores section' on my profile." Which might be a good reason not to add have it unless it were somehow possible to keep track of all the highscores, which you basically just said wasn't possible (you'd have to manipulate the game code itself of the games that couldn't be tracked to track them, I assuming. And that would probably break some sort of agreement with the developer of the game and take a long, long time to implement for each game, even if the developer (s) agreed.)