Most beginning cyclists and recreational riders who don't even think of themselves as cyclists consider standover height to be the most critical dimension. Don't want to imperil the tender parts. And insecure cyclists want to be sure they can put the landing gear down instantly in an emergency.
More experienced cyclists, especially riding hard and racing, realize that the length of the bike from seat to handlebars is more critical than the height of the top tube above the ground.
Workable cockpit length can vary over about two centimeters. Because humans are made of squishy and elastic materials, they will fidget and shift anyway, making the idea of some millimetrically precise perfect length laughable. However, go one centimeter beyond the range either way and you'll suddenly feel all the distance from the middle of it. The bike won't just feel a hair short or long.
Bike fit is made up of numerous factors. Ideal fit will be different depending on the use of the bike. This is obvious to most experienced riders, but not to casual cyclists, even if they feel its effects. A good fitter will figure out how to set up a bike without requiring the rider to know much about it. The more serious a rider plans to be, the more the fitter will need them to participate. It's not an exact science, but it is a developed art.
I just put a shorter stem back on my fixed gear. The cockpit had felt a little short, but when I went the extra centimeter it felt way too long except when I rode with my hands on the bar tops. I kept it that way because I commute a long distance on open roads by myself, so I spend a lot of time on the center of the bar tops compared to more urban commuting with traffic.
Only having one brake, I don't have the extended riding position on top of the lever hoods, as I do on the 'cross bike and the road bike. With the long stem, the turn of the bars on the fixed gear fell close to the hood position on my freewheel bikes. But the long stem made the drops too far away. When I went down and forward I lost power because I got pulled too far forward of the cranks. My back hurt because I kept trying to grow an extra vertebra to make up the difference.
I could put an aero lever on for the one brake and a dummy hood on the other side, but I like the clean look without it. My brake lever is a vintage Campy Record with the cable coming out the top. It's attached to a drilled out "Weinmagnolo" my machinist friend doctored up for me in 1975. The stiff Campy lever gives the modest old Weinmann center-pull a little more authority than it got from the Weinmann lever I had on there originally.
We just need to get this snow out of here. I'll start riding anyway, but it seems more abusive when it looks like February.