I find myself ignoring the whim system at times because rarely do whims pop up that are relevant to the sim I am playing, other than the emotion that they are currently feeling. What kind of whims they get should be driven by their traits. If I give a sim a trait, I want them to live out their life according to their personality. They should want to do certain things.
This system feels like your computer randomly suggesting things to do, not ideas coming from your sim.
Long ago I suggested that one of the bubbles should be dedicated to trait related whims, like emotions has its on thought bubble. The third bubble could be dedicated to other miscellaneous whims.