Eh, I took it in one of my Yellow runs, as per my Versus Guide's advice, given the low count of Fire-types in that game. Dunno how much I actually used it, though.
flareon has one of the highest ATTACK powers of all FIRE pokemon in the game, in fact on par with Ho-oh. unfortunately the amount of PHYSICAL fire moves it can actually learn is just one and its mediocre at best, while it does have an arsenal of SPECIAL ATTACK powers, its SPECIAL ATTACK to begin with isnt very high thus making flareon kind of a sucky pokemon
Beedrill doesn't bring much to the table with how much Bugs sucked back in the day. Primeape isn't bad, but it's really just a placeholder until you can get a Machamp/Machoke or Hitmonlee/Hitmonchan for a dedicated Fighter. If he's got Articuno, I have to wonder why he doesn't have another legendary. Moltres could fill Flareon's niche, for instance. Vileplume and Blastoise are good to go, though. Vileplume can fill the status debuff annoyer roll so many Grass/Poison types specialize in, while Blastoise is ten tons of awesome.
Nerdy nitpicking aside, it's an amazing image. Oca is bleeding talent.