I used to ride medium sized frames as seat tubes were historically too long. The reach was scarily short on some older bikes with short stems. I'm 5,11 and ride large size now so in many ways the jump to modern geometry and fit has been compounded.
I remember buying a custom built ht frame (Curtis SX) in about 2006 and requested the longest top tube (22.75 inch). The builder quizzed me at the time suggesting it may be too long but it felt great at the time having a short seat tube and longer reach.