Angie can correct me if I'm wrong, but I think whiskering and bunching are more of a factor of hip and/or thigh width. Whiskers would indicate too tight in the hips and/or thigh pants, and bunching too loose in the hips and/or thigh pants. That has been my experience, at any rate.
Although it's probably true that if your rise is too long you might get bunching - but it'll be a different kind of bunching. The zipper will bunch. If your rise is too short AND your pants too tight, you'll get the dreaded camel toe. Eek!
Rise length is often also a matter of preference. I like to "lock and load" the squishy parts of my belly, so I like the rise to hit just below the belly button, where everything is squishy-ess. For me (I'm 5'0") that is about 8.5-9 inches.
If you have very little squishiness in the tummy area, and if you are a pretty pear shape, you probably look better with a lower rise.
In general I think you know if the lower rises aren't for you. Because you get this gut ledge overhang thing going on that isn't attractive nor comfortable.. no matter how loose and long your shirt is!
Back rise is just as important, in my experience. Too long of a back rise leaves a saggy shapeless butt, if you don't have much of one.
