Although similarly-named Pokmon-EX were present during the XY era of the TCG, they were always Basic Pokmon (or Mega Evolution), even for evolved Pokmon such as Charizard, meaning actual evolution cards (Stage 1 and Stage 2) became less and less used and the gameplay was focused more on hard-hitting Basic Pokmon
You get a lot of versatility and power when you create token copies of creatures and artifacts, especially when you copy artifacts like Monkey Cage that were never balanced around becoming a creature
Rare Pokemon cards can be incredibly expensive, so they are likely to attract scalpers, and restrictions could have been implemented sooner to address the issue before it happened
Threshold If seven or more cards are in your graveyard, seek a Rat card
Totally fair
Mileage varies between players and playgroups, so my experiences may not line up with everyone elses, and thats okay