I've sampled what seems to be countless ponds that contain crappie. The good crappie ponds always seem to have the following characteristics: high bass densities, fairly clear water, decent amounts of submerged aquatic vegetation (10-20%), and the crappie are generally black crappie. Crappie are an extremely prolific fish. The clear water and the high densities of bass help to "control" the crappie numbers (i.e. lots of bass need to be able to see the crappie in order to eat them).
Without the bass, you have a good chance of seeing your crappie numbers explode. If this happens, you can probably expect poor growth from the crappie. Lots of folks around here love crappie, and it takes a devoted pond owner to establish and maintain a good crappie population. I generally recommend a "catch and release" bass fishery for these folks. I say let the bass overpopulate, so that they are able to help you keep the crappie numbers under control which will inturn provide better crappie growth.
You don't want to run into a situation where your crappie become overpopulated- unless you don't mind fileting 6-7inch crappie. All in all, I see poor crappie populations more than I see good. The poorest crappie populations almost always have poor water clarity and few bass.
There are always exceptions. If you love crappie, my advice to you is to go for it but keep good records and realize that it will take some work to keep things going.
