It will not lead to a dieoff the overall pounds will be basically the same just more pounds will be in bass than in bluegill if left alone. It will go towards lots of skinny bass. You are doing the right thing by taking out when you can if your goal is larger bass. If goal is large bream then you will have that upon return. Not the hardest thing in the world to remove enough bass in a half acre pond. If you fish right time of year you might be able to remove 10-15 lbs with a couple days of fishing. This might be enough to keep it in balance.
