Most classic sewing tables have a central and glaring ergonomic flaw that few have attempted to tackle with design. The flaw arises from an unskillful negotiation between what the user needs and what the physical dimensions of the table provide.
The central problem is that a sewing machine operator should be centered on the needle of the machine, which is off to the left side. They must be able to clearly see what the needle is doing and use both hands to guide the fabric. But most sewing tables are trying to fit a 15-inch wide machine in an unobtrusive footprint, so the designers would center the machine in a table scarcely wider than the machine itself. Thus, when the operator sits at the table and places their legs in the space allotted, they are centered on the machine itself and must lean to the left to get their noses in line with the needle. If you shift your seat over to be centered on the needle, you hit your left leg on the left table leg. I wonder that there's not a generation of 20th-century women with S-shaped spines.
One table that actually addressed this problem, tackled it with creative design, and even added some Mid-Century Modern flair is Singer's No. 74 "Spinet" Cabinet, which is shaped like a trapezoid.
The front panel swings open to the right...
...allowing you to pull the table's left-side support, including the front left leg, out to the side.
The top can then be flipped to the left, coming to rest on the moveable leg.
Getting the front left leg out of the way centers the operator on the needle and provides more generous legroom.
The trapezoidal shape of the top provides a slight wraparound effect when open. Additionally, since the open tabletop is now resting on an actual table leg rather than a swing-out metal bar, it has more significant support. Lastly, the trapezoidal shape looks stylish as heck when it's all closed up.
I consider this design an all-around winner, and am surprised that we never looked at transforming mid-century furniture like this in our History of Industrial Design classes at school. And sadly, the original designer's name is unknown.