"...in charge of constructing such a bunker..." —
This is a phase of the modern golf course, preoccupied with construction and trying to re-create. Bad? Not at all. But this discussion is about shape and opinion about circular bunkers. I find it odd we should care that much about shape — round, square, flower-like, oval, coffin, cigar, or Desmond-inspired fish. Well, come to think of it, Desmond's fish may well deserve an entire thread on shape!
Bunkers, in origin, were not usually constructed. They evolved from wear and tear, natural oddities in the land, and the occasional urging of man. Their shape was of no concern, at least not much. What happened, simply happened.
I doubt seriously whether the scholars of St. Andrews sat around drinking and contemplating whether a roundish bunker would look better, let's say, than one with a nose or two. Or whether a circular bunker would be less interesting than one with several lobes.
No. They simply thought it a decent idea to "help" the maddening hole which had developed behind the (now) 4th green by digging it larger or deeper. If there was leftover soil after their assistance, it had to go somewhere and perhaps a wiggle or nose was the result. Or maybe the soil was thrown toward the back, creating a higher bank.
These scholars prioritized: Location, size, depth...and then, perhaps, shape, but probably not much. I will guess that our ancestors of golf architecture never really cared about attempting to outpace nature when it came to aesthetics.
Now...get back to work!