It was rushed to meet the Wii's Japanese release and is lacking so much content in comparison to prior console battle simulators. It was at most 40% of a game, and the reveal trailer looked a lot better. It really needed another two years of development (and to be combined with Ranch) for it to be a true Stadium successor. I'm alright with a lack of a single-player RPG ala Colosseum and XD, but really, the only game worse than this was the original Japanese Stadium. It can't be overstated how sad of a game it and Ranch were.
Weirdly enough, I found out somewhat recently that PBR had updated versions only ever used in certain official tournaments. There are videos of Platinum Lucas and Dawn battling each other (and this presumably means Origin Forme Giratina, Sky Forme Shaymin, and the Rotom forms are all included).
Overall, they should have released it in late 2009 with HGSS compatibility and billed it as a Stadium GS remake with every Pokémon up through Gen IV.
