While "EvilTwin's Trouble Sunny" provides good interruption during the opponent's turn, mass removal cards such as "Raigeki" or "Lightning Storm" can prove troublesome for the deck, as even if player tributed "Sunny" in response to the activation, the effects of "Ki-sikil" and "Lil-la" summoned by "Sunny's" effect will not activate upon chain resolution before both were destroyed, leaving the player vulnerable to opponent's counterplay
Huatli, Dinosaur Knight already existed as a fairly weak dino-centric planeswalker, one you can even fetch up with Sun-Blessed Mount
Sometimes, being a stronger Pokemon doesn't guarantee it will have a more valuable Pokemon TCG card, as Fuecoco eclipses Skeledirge
The Graveyard Whether its because we have grown bored of a deck, new cards have come to replace old staples, or we drift away from the game entirely, eventually all of our cards are destined for obsolescence