Fish: I agree that DS developers shouldn't _have_ to use the touch screen. However, it's a problem, because a lot of people do expect it at this point.
Word is that Kirby is taking the touchscreen design beyond gimmicky. For that matter, I think Yoshi Touch N' Go takes it beyond the gimmick, the only problem is the game isn't a full-blown 2D platformer like many were hoping. I think it shows that a full-blown platformer could be done with the stylus, though. I think Nintendo went with a simpler puzzle-action-high-score design simply to get the game out quickly.