A cog has a very specific definition of shape. The one shown there very clearly looks like a bad rendering of a cog, while the other clearly represents a cog. I would not be happy with the "thinner" cog either. Puke.
Details like that are what differentiates artists from those who lament "I wish I could draw/ paint". We see the details, and obsess over them, and they are oh so important. A face is made up not of the whole, but all the little details; down to the cracks on your skin, and the tiny hairs you never notice. If even one were missing, you would not be replicating the object correctly, and it would be "off".