Well it's a good thing they fixed the cloning glitch. If anyone could clone any given Pokemon at any given time, then the wonder trade could become over-saturated with event exclusives, thus defeating the purpose of "event exclusives" as "nice-to-have, one-of-a-kind Pokemon that mark specific events."
While I am someone that loves to find exploits in a game, I refuse to use exploits in games that are part of a community network, where such exploits could negatively effect the overall game-play experience. A good example of this exploit ruining the game experience would be: For a given Level 100 Pokemon, clone it, and trade it for other Level 100 Pokemon. Then the vast majority of random matchups could have such high-level Pokemon, that it discourages other players from participating in the community that The Pokemon Company and Nintendo wish to create.
Nintendo has taken steps to discourage hacking. First of all, you can easily get banned from the Nintendo Network now via Nintendo Network ID. Because you can only have one Nintendo Network ID per system, with no alt accounts (unless you have multiple systems or don't mind factory resetting your system) they hope to keep players in check. I'm even confident that if Pokemon Bank does get hacked, there will be a title update that will require Pokemon Bank to be updated to continue to function with X and Y, most likely by having another X and Y "patch update" that would block online interactions until both software titles are updated.