In fact, The Pokemon Company has just confirmed that it is preparing to release another new line on May 5th for the TCG called Pokemon Sun & MoonGuardians Rising
Expect the English gold to follow the same launch-spike-then-fade curve, likely with a wider spread than the SIR because so few copies change hands
But think of it this way: when you export your deck, you create a new meta, collapse an annoying one, or form an alternative to an existing, solid deck
Theyre rare and short-printed, but not extremely so
Each world has its own creatures and civilizations and weapons and wardrobe
A lot of balance and care goes into choosing the cost of a card, more than I can express here, but looking for similar effects on existing Magic cards can give you an idea of a fair costfor example, a ramp spell that puts two lands into play ought to cost 4 mana, per Explosive Vegetation