Considering there are already several unofficial Pokmon TCG apps that do support older sets, this seems like a poor choice on the Pokmon Company's part when it comes to meeting the needs of classic Pokmon fans
It gets better, because The Ur-Dragon draws you cards whenever a dragon you control attacks and then lets you put a permanent on the battlefield from your hand
Nissa, Who Shakes the World is cleanly answered by Noxious Grasp, as well as Teferi, Hero of Dominaria
Effect: You can Special Summon this card from your Graveyard by banishing 2 LIGHT monsters from your Graveyard
Blossom Bombardment!" When Akiza activates "Doppelganger" or its effect, she announces "I activate my Continuous Trap, Doppelganger!" When Akiza activates "Fragrance Storm", she announces "I activate my Spell Card, Fragrance Storm!" When Akiza activates "Half Counter", she announces "I activate my Trap
Right upon its release, Arven is likely to be played in Miraidon ex (which plays both Forest Seal Stone and a powerful new Item card Ill mention later) and in builds of Gardevoir ex that run Sky Seal Stone