I guess it depends upon your priorities and the water you are fishing. I believe research indicates that bluegills can delay maturation until they are larger. Once they become sexually mature, much of their energy goes towards reproduction instead of growth. Most eggs go into the center nests typically held by the largest male bluegills. Thence, if male bluegill delay maturation until they are closer in size to the largest male bluegill, you will have a better bluegill population / size structure. In my own ponds, I intend to harvest mainly the intermediate size bluegill 5 - 8 inches and let the larger ones spawn until such time as I believe them to be nearing maximum natural lifespan anyway. My lake is still young so I'm not sure what I'll do at that point.

http://www.inhs.uiuc.edu/caec/research/currentproj.html