According to the Japanese Pokémon website, some rule changes for the TCG will be happening with X & Y.
1) The player going first cannot attack.
2) Pokémon Catcher now requires a coin flip. If heads, you make the Pokémon switch (like Pokémon Reversal).
3) A new Supporter card, Professor Sycamore, has the same text as Professor Juniper. Therefore, you may play one or the other in your deck, but not both.
What do you think about these changes? They are set to be put into place in Japan on November 8th.
Full information can be found at the Japanese site: http://www.pokemon-card.com/howto/new-rule/index.html