Are you mostly excavating a "basin" for the pond, or are you constructing a dam to block a pre-existing valley? (That is a slightly oversimplified version of the two types of ponds.)

Sharp corners are good to draw on paper and good for carpentry. However, they are tougher to build with dozers. You probably will need to round the starts of your peninsulas, and also round their final terminations (unless your are going to reinforce with lots of rock).

Most ponds in warm, sunny places like Texas eventually develop too much floating algae and bottom-rooted plants - so the goal is to have steeper pond slopes so a higher percentage of the bottom of your pond is not in bright sunlight. However, there is a limit to the slope that can be held by your soil type. In practice, the usual steepest slope is probably around 3:1. (Which is for every 3 feet horizontally, the pond gets 1 foot deeper.)

In my (non-expert) opinion, some variance in the pond construction will actually improve the overall ecology of your pond. The areas of the pond that receive the most sunlight to the bottom also tend to be the most productive. Therefore, you do need SOME shallow water. A few areas with some 4:1 or 5:1 slopes might be beneficial. Also, some areas with a slope, then a flat bench (for spawning, etc.), then another slope to deeper water.

Your deepest water will typically be the least productive portion of your pond, but it is still very important. If your pond is in the drier portions of Texas, you are guaranteed to face a drought at some point. Your pond could go down 6 feet (or more) in a drought. The extra water in your deep spots will hopefully get your fish through to the next rains.

The deep water also provides some thermal mass that keeps the pond cooler in the summer. One important benefit of this aspect is that cooler water is typically saturated with more oxygen than warmer water. Hot, low-oxygen water can result in summer fish kills. Are you going to aerate this pond? That is the best supplement to some deep water to avoid fish kills.

Finally, a bit of "extra" deep water is important because your pond will fill with a little silt immediately after construction. The construction process will leave a lot of bare ground in the basin, and any significant rains will start eroding that material right into your pond until you get good groundcover plants established. Further, are there any plowed fields in the watershed for this pond? If so, then you will also receive some sediment in the future when there are heavy rains shortly after the fields are tilled. A little extra depth can accommodate some of that sediment. It can also accommodate some of the organic muck that will also eventually accumulate at the bottom of your pond.

Another consideration is that the pond builders are not carving a uniform chunk of marble to make a work of art. There will be some variability in the material you are moving. If you dig past 12' deep and encounter a sand lens, then you will either have to re-bury and compact clay-rich material on top, or dig down to a deeper depth and determine if you have reached the edges of that type of leak making material. Unless your design is completely constrained by the location of a house, the property lines, etc., then a little flexibility in the design to follow the easier path through the subsoils can give you a similar pond that is less likely to leak and for much less money!

You also need to add the goals for this pond in your post. Trophy bass pond? Eating size BG? Some decent fishing with lots of family water recreation? There are members that are experts in all of those topics and can give you more comprehensive advice.

Good luck on your new pond project!