What would Charizard "fuse with" to go to OU? As it stands (copy-paste my Charizard/Volcarona essay):
Volcarona gets Quiver Dance, one of the two Gen V moves that is in contention for "best boosting move in the game". (The other one is Shell Smash). It also has Bug as its secondary STAB, which only overlaps with Fire on Grass-types, giving it 6 types hit for Super Effective with STAB instead of 5. Volcarona's stats are tailored for using (and also taking, to a lesser extent) special attacks, and using them fast, while Charizard's are mixed. Volcarona's average stat is 92, and its highest is 135; its BST is focused in mainly Sp. Atk. Charizard's average stat is 89 and its highest is 109; its BST is much closer to evenly distributed.
So, in other words, Charizard is a Pokémon that was designed to be a good starter; it is a jack-of-all-trades that looks awe-inspiring. Volcarona is a Pokémon that was designed much later on, by someone who was aiming to provide an Pokémon that could do one thing well. Jacks-of-all-trades need better conditions to do well--Manaphy gets Tail Glow and Hydration, Mew learns all TMs, Victini gets V-Create (which would be a lot better if Rayquaza didn't get it too), Arceus beats every Pokémon in at least one stat, et cetera. Thus, Volcarona and Charizard have different levels of competitive viability.
For those of you starting topics about the PS4, there's a PS4 board: http://www.gamefaqs.com/boards/691087-playstation-4