Rushed, you say? It's possible. Work was being done on the DS games in 2012 still. I was disappointed because BW play very fast, especially on a DSi (they're DSi enhanced), which really kept me hooked. 4th gen was slow and 3rd gen was fast but had bad visuals IMO (I don't like some effects and animations).
It really pains me to say this, but you were right with regards to Pokémon and the 3DS. The framerate is... disappointing. It's killing my enjoyment of the game.
About the flames, it seems they modeled the flames onto the model of each Pokémon (like on Charmander's tail), which was a terrible choice. They should've used effects like in the console Pokémon games.