To my knowledge, I don't think they have. However, I'm not the brightest on Pokemon events. Either way, the answer would simply be that there is a possibility they will re-release, or they might not. We will just have to wait. >:3
As for your side question, they did this to prevent items that don't exist to be in other games. For example, if you traded a Pikachu with TM45 (whatever that is, I dunno. xD) to Pokemon White 2, it would be pretty invalid because those games don't have TM quantities. TMs can be reused in those games, and they are pretty much like key items. This is the same for the Exp. Share - in Gen V, it was a normal item, but in Gen VI it is a Key Item, and the normal Exp. Share Item doesn't exist in Gen VI, and will probably cause the game to glitch up. xD
So yeah.
Hope I helped. :)
Source: Knowledge