My daughter received Pokémon XY cards for Christmas, and I have been thinking about buying a deck to play with her. She has the XY trainer set, and I was looking at the other XY cards to buy. Then, though, I considered the old Team Rocket and Team Rocket Returns sets. These would be fun, as I could clearly be the antagonist, thematically.
I understand that these cards would not be tournament legal. That will not be an issue.
Are they relatively balanced, though? Do later game changes like EX cards and Break cards fundamentally shift the balance toward XY series, or are they just changes in how one constructs a deck? Can I play a Team Rocket (Returns?) deck against an XY deck and not consistently lose because of changes to cards over the years?