I would agree. I see the bluegill nests in 3 to 6 inches of water along the shallows of our pond.
You need terrain and not just a big "soup bowl" if you want a fish pond.
I think you need a balance between trying to keep plant growth under control. If you want a fish pond you need and want areas of plant growth. I would also add pea gravel spawning beds in the shallows. It looks like you have lots of clay and lager stone. Blue gill love pea gravel to bed in. We added a load this summer and it amazing to see all the bowl shaped hollows that showed up in about a weeks time.