I am new (began at around the release of Scholomance). I missed out on almost all hero skins, too. However, I believe that hero skins should not be re-released as part of their prestige is to represent that the player using them played at the time of the sale. This signifies that the player is a veteran, for instance.
I do strongly feel that the most recent Jaina bundle and included skin should be re-released, however. Here is why (please read):