...well, yeah. The entire purpose of the game is to battle your own trained Pokémon in 3D on the Wii and online; why even bother with it at all if you don't have the aforementioned trained Pokémon and the system on which you do that sort of thing and by that same token, why grade the game down for that being a key element?
Did you, at any point, think the game would really hold anything for you if you didn't have trained Pokémon to use with it? You might as well criticize a game for being useless if you don't have a single controller to use with it; it's about the same thing.
None of which mark a game as being the "worst" anything.
In that case, why even make the game if all it is is a 3D Pokemon battler with none of the extra features the earlier 3D games had?
I didn't like it because it was so goddamn easy. I know that that doesn't necessarily ruin a game, but from what I can remember, the opposing Pokemon were weak and had the worst movesets. I know because the Roulette Cup gets its difficulty if you just so happen to get none of your Pokemon in the pre-battle roulette, and the Select Cup is annoying because you have no choice but such Pokemon, many of which you have seen a thousand times.