Always the same emotion.
I agree that that's a problem.
And definitely a point where such games differ from art.
To draw upon Robert McKee's ideas about story (as I described briefly
here), what these games provide is not "emotion" - it is a bunch of emotionally neutral changes in value, positive (with success) and negative (with failure).
In order to be "emotion" (by this definition), the neutral value changes would have to be tied to an emotionally resonant "mood" that provides context. Kind of like a wind instrument - the value change is the vibration created in the mouthpiece, and the mood is the resonating chamber that locks and amplifies the initial vibration into a pitched note. The better aligned the gameplay (neutral value changes), mood, story, and setting, the more likely that the player will experience emotion beyond the bland sweetness of virtual coins and levels.
This is not easy, but I believe it is possible. Lately I've been encouraged in this direction by the apparent success of my little (not)game
The Love Letter. This article has a great discussion of how these elements align in The Love Letter to create an experience that is more than the typical neutral pleasure of gameplay:
http://www.slowdown.vg/2012/02/25/on-the-love-letter/