There is a breed standard for a reason, though. The making of the breed took years, and size was certainly a consideration when it came to the Doberman's athletic and working ability.
The Doberman, however, is supposed to be a medium sized breed. The AKC standard lists the "appearance is that of a medium size, with a body that is square. Compactly built, muscular and powerful, for great endurance and speed." More specifically, the standard says "Height at the withers: Dogs 26 to 28 inches, ideal about 27 1/2 inches. Bitches 24 to 26 inches, ideal about 25 1/2 inches. The height, measured vertically from the ground to the highest point of the withers, equalling the length of measured horizontally from the forechest to the rear projection of the upper thigh." Bigger than that, and there may be undue stress on the joints, resulting in an unsound dog. A working dog that can't work.
"Warlock" does have historic precedent, as it were, but did not originally mean a BIG dog. Borong the Warlock was shown in the 50's and 60's, and according to the linked site, was an American, Canadian, and Cuban (!) champion, in addition to having his first Obedience title CD (Companion Dog). My understanding is that his disposition was fantastic as well. Champions aren't oversized dogs; they fit the standard. An oversized working dog cannot adequately perform the work for which she is bred; her endurance suffers for it, and her maneuverability.
Elka is oversized for a female Doberman. She's 28 inches at the withers, but she's also square. She weighs 71 pounds. I don't know what her sire's measurements are, but to my unschooled eye, when I met him, he was a pretty big boy. Elka isn't a show girl, and I didn't buy her to be such, and even though she's young and strong and just fine, I worry about how her joints will be as she gets older. I might be worrying for nothing; she isn't huge, and were she male, it wouldn't be an issue in my mind. When we got her, we didn't pick the biggest puppy, but rather the one who reacted the best when we interacted with her (in our eyes). Temperament is very very important in my eyes, and really, show girl or not, Elka is my pretty girl and that's good enough for me!