> There was a guy at work who insisted on using .format() for everything that soured me on it, sometimes even simple string concatenation

It sounds like you are soured on new-style .format() because someone else doesn't use it appropriately. You concluded that it's intrinsic to .format(), even though s%{} is even more verbose, because of what seems to be an idiosyncratic preferences of one person.

I empathize with your other arguments. I too am much more familiar with printf-style % arguments than the Python-specific .format() syntax, which still cause me to reach for the documentation. But I do not think that it's reasonable to complain about its verbosity.