>>36327938It didn't have enough moves. It got a useless Hidden Ability.
It needed to be a better Status move user with more options for an attacking build, such as expanding on its Dragon capabilities.
The best moveset it can have at the moment is Leech Seed, Substitute, Double Team, and Toxic or Synthesis. That's way too generic with no distinguishing BST spread or abilities to entice players to use it over something like Whimsicott.
It wanted to be bulky, but powercreep demolished that image of it. Only an ability as blatantly overpowered as Filter, in an alternate universe where Pokemon like Talonflame never existed, could it have had a chance at gaining respectability in its future.
As it stands, the stat of the game at the end of Generation 5 offered it nothing compelling that it could have drawn upon.
>>36327955is lazy both design wise and lore wise but where better Pokemon like Venusaur get Sleep Powder and Sceptile Grass Whistle, it could have distinguished it more.