I live in Cleveland Texas. The area we dug my pond in is clay, and a low area of my property. When it rained, it held water until it evaporated. When I dug the pond, we found some really hard clay, packed, so hard we could not dig but a few inches at a time with a 200 series track hoe when we reached it. Due to this, there are areas that are only a couple of feet deep. My questions is can a pond be too shallow? About half of the 3/4 acre pond is about four to five feet, the other half is only about two feet.
I know of a guy about 10 miles away that dug his pond deep, about 15 feet and went through the clay. Now he has problems with his pond loosing water, I don't want that.
I plan on redigging it next year by lowering the level down about two feet and bringing in a bigger hoe, if finances and the wife allow.
The pond is well stocked, and I have not seen any fish kills, I keep it aerated with a waterfall and fountain, so it seems healty.
What are your thoughts.

Yes, I think a pond can be too shallow. A pond that is shallow can let sunlight to a considerable amount of the pond bottom, and where sunlight hits, weeds will grow. Depending on water clarity of course. A shallow pond also heats up and cools down quicker. IIRC I think a while back (years) a cold rain was the reason why there was a fishkill in a pond.

During periods of low rainfall, they are also more prone to going dry.

Esshup pretty much covered it. When building ponds here, we try to go at least ten feet if the ground will allow us.