Yakuman Wii: Ide Yousuke no Kenkou Mahjong wouldn't be terribly interesting. Even if it's a new WiiWare game, mahjong is happening in most of these screens, and that doesn't translate into compelling preview content even for fans of the game.
But we're fascinated by Nintendo's decision to use not-Miis as its AI opponents, in a game that includes Miis. Why do that? Why design characters that look sort of like Miis, have similar proportions, but aren't Miis? We understand why the Ide Yousuke character doesn't necessarily adhere to Mii guidelines (to more accurately depict a person), but even he's more Mii-like than these alternate-universe Miis.
Each of the characters has a different play style, which is described in the profile next to the name. Atsuo, here, is a "defender." The stars, we believe, indicate a difficulty level. There are lots of other screens available at GAME Watch, ranging from mahjong happening to mahjong about to happen (Wi-Fi setup, lessons from Ide Yousuke) to mahjong just happened (multiplayer results).