First, I didn't mean to draw a distinction between Teimanim and Sepharadim in this, although re-reading my wording was unclear. Some older Sepharadi texts also have this slightly pointy shin, and some Teimani ones have a rounded shin (there are some big distinctions among Teimanim for one). For those that write shin with the little point, they would be unimpressed and probably offended to hear the explanation that it's to accommodate Ashkenazi interests, especially since the Mishnah Berurah's ultra-pointy shin is a later development than the slightly-pointy one. Check out the book מסורת האותיות to see that early Ashkenazi writing was much more similar to what we think of as Sepharadi, e.g., more rounded, less stuff on the letters. The book made many people (Hareidim I guess who have a vested interest in promoting their current Ashkenazi shitah as ancient and eternal) furious when it came out so he re-released it with photographs of the manuscripts he found.

Not that there aren't differences, just that they aren't as exaggerated as they can be today, and as you'll see if you look there are examples of much more rounded Ashkenazi shins.

Anyway, about what completely-rounded people say about the Gemara excerpt. I think they would simply interpret it to work for them, namely, say that a rounded line like that does indeed rest on a single point when it comes down to it, unlike the solid bottom of, say, a mem sofith.