I have a question, guys; I was trying to transfer one of my Pokémon earlier today, but Bank blocked it. It was hacked, but not badly, though. Am I doing something wrong? Thanks in advance. :)
Well, what you were doing wrong was trying to transfer a hacked pokemon.. you answered your own question xD!!
but if you want a real answer, here's the criteria that Pokemon Bank Blocks according to ProjectPokemon.org:
1. Jirachi (Shiny, from the RNG'ed save)
2. Pkmn with DW ability that is not released
3. Wrong location (i.e. caught in mystery zone or somewhere it can't be found)
4. Bad hacks (i.e. invalid byte data, has moves/ability that it cannot have, invalid EV ranges, Invalid IVs + Invalid Personality Value, Invalid Nicknames, Invalid Origin info (i.e. marked from black 2, but should of been from platinum), invalid pokeball, etc)
If you're creating your own hacked pokemon :| (how dare you!!!) there's always resources like pokecheck.org where you can upload your pkm file or have it nab it (clone it) from the GTS, then you can run a "Legality Analysis" scan on it and it will tell you of any errors, invalid data, etc.
If it's all clear on there, then it will most likely transfer to X&Y.. but if it has errors, then the chance is high that it will not pass Pokemon Bank.
If you see a post I made here on the Pokemon Bank's release date, I asked the question if anyone else had issues trying to transfer their pokes over Pokemon bank, my 6IV Xatus and battle Mewtwo were refusing to transfer, even though they both were legit as far as I knew (i bred the xatus myself), but turned out Xatu was bred down from a line that originated from a hacked pokemon that I must of used during the early breeding process, and mewtwo had some error with it's trash data.. i solved the issues by having pokecheck clone them through GTS, downloaded the pkm files it created, then was able to wipe and correct the errors it showed (basically just had to save a fresh copy), then I uploaded it back to pokecheck and it showed they had no errors, then transferred them back into my Black 2, and voila! they were fixed and were able to be transfer into X&Y with no errors.
For example this Bidoof *cough*GODoof*cough* that knows moves that it shouldn't :| such as Judgement, Roar of time, has an incorrect PP range, and invalid nickname:
https://www.pokecheck.org/?screenshot=4813057&la