I know a little bit about pond management. I'll try giving you as much info as I can..
With the backround of your pond being 2 acres, according to what I've read you probably have 30-50+ mature bass (3 pounds or more) living in the pond. You say that the bass are overly aggresive, by eating sunnies whenever you hook one. I would think that there might be a lack of food within the pond, so when a bass sees a sunny strugling (from you hooking it), each bass is trying to eat it before another one does. You might have a good population of large bass, but if you want to grow trophy bass 7 pounds and larger, I would suggest harvesting roughly 15-20% or so of the mature bass. You might want to keep the larger ones and harvest about 5-10 bass 3-4 pounds. Bass need food to continue to grow and with a lack of it, the bass will still grow but they will become skinny and not gain as much weight. I would rather have the bass nice and fat, than a bunch of skinny ones. You might also consider stocking the pond every 2 years or so with sunnies and other minnows. It is good that you have some big sunnies (1 pound and larger), that way they will continue to reproduce without bass eating them. I would also advise you to contact a fisheries biologist and seek their advise.