I'm probably a little late on this since you have decided against the rip-rap but..
I built my 1/2 acre pond in October of 2003. It promptly filled later that fall. During the dry weather we had in August of 2004 the pond receded to an all time low of almost 2' below the overflow, exposing several feet of unsightly clay bank. The pond is only about 100' out my back door and I personally did not like the way it looked. There was a distinct erosion line around the pond caused by waves below which no grass would grow. We used this line as a guide to place geotextile fabric followed by about 90 tons of #2 limestone delivered and placed by "slinger" truck. It stopped further erosion, gives the little fish and other creatures a place to hide and has reduced the amount of trimming I have to do. The price seemed pretty reasonable.
Keep in mind that if the water level drops 1' on a 5:1 slope, 5' of "natural" eroded, plantless, clay bank will be exposed giving good opportunity for crabgrass and other weeds to take root. The rip-rap and geotextile fabric also make it very difficult for cattails to get started and the water stays clearer.
Here it is right after placement
Here it is 2 years later when the pond is full
