The large number of mons from gen III that I'm generally uninterested in or just don't care for at all outweigh any of the small number of ones from any other gen that I dislike to any greater degree. It's hard for me to even name more than a few from gen III that I actually like.
I LOVE Gen V's pokemon, in fact I would have put it at the top if I ranked the Gens for 'best pokemon in general'... but I will also vote for it here
Stunfisk >:( Is he supposed to be a whoopee cushion pokemon or something? It's cry is terrible, and I can't stand how FLAT he is, it looks stupid as hell in battle. Battle-wise its like the developer(s) responsible for Stunfisk just mashed a random number generator and decided that was enough. 'Trap pokemon' without any trapping abilities or moves (barring Infestation which it only got this gen), an entirely random movepool of niche-use attacks, including attacks like Revenge, Bounce, Pain Split, Uproar, Camouflage... WHAT IS THIS THING SUPPOSED TO BE.
I was fine with most of the cast, no matter how much of a joke/trash they were. Until this... thing... made his debut.
Oh yeah it still has Limber as an ability even after the fact that electric types can't be paralyzed anyway, and to be honest the fact that it was ground type made it dubious at best to try and paralyze it in Gen V in the first place. Sigh.