The premium items they seem to be putting into BC Classic look like they're meant to replace the TCG Loot items that started being introduced in 2006, since there are also tags for the Dark Portal Hearthstone and the Path of Illidan items.
Those Loot Cards came from later sets in the TCG (Hunt for Illidan and Betrayal of the Guardian), but match the theme of the expansion (Black Temple and Black Morass), so it would make sense to move them around.
And since the mount Loot Cards are still rare and are worth a lot of money, they're replacing them with completely new mounts so as to not devalue the original Spectral Tigers and shit.
That's my guess, anyway.