It appears that there has not been a single mentioning of the Pokemon Stadium/Colosseum/Battle Revolution.
One of my guesses is the as far as Nintendo is concerned, people are only interested in Wi-Fi battles on their DS games. Another guess is that Nintendo has become so cynical that they figure people mainly play the Stadium games to see their Pokemon in 3D, so they give us Pokedex 3D/Pro. "Let's just give them all the pokeyman in 3D on a pokedex and have them scan markers to collect 'em all!"
Only half-hearted satisfactions that take away from the original Pokemon Stadium 2"
-Minigames: Go play PokePark Wii/Wonders Beyond
-Gym Leader Castle: Go play Pokemon Black/White 2's World Tournament
-Your Room: Go play Dream World
-Game Boy: Don't care. Or. No need/irrelevant
-PC Storage: Since Pokemon Box and My Pokemon Ranch, nothing else has come out.
But they forgot just two things, the fact that you could use "uber" legendary pokemon freely in certain stadiums (Prime Cup, Gym Leader Castle, PBR). Meanwhile, those are banned pretty much anywhere in B/W but link battles with close friends. Oh, and what is there to do with Level 5 pokemon for the sake of Little Cup (especially you caught Relic Castle's Volcarona, but barely trained your hatched Larvesta, or obtained Braviary/Mandibuzz in a trade (since you never see their prevos in NPC battles (depending on which version you have) so you can't request pokemon you never saw from GTS), but bred Rufflet/Vullaby to complete your pokedex).
But still, they make an edgier "sequel" to B/W (still in the same generation), at typing game, another mini-figures game, another mystery dungeon game, a Nobunaga crossover, a "sequel-exclusive" app (Dream Radar), and a TCG tutorial.