I see a lot of the pros doing this. The 5'9 guys riding a 52cm with a 130mm stem or a 6'2 guy doing the same on a 56cm.
I ask, why?
I understand there is weight savings and the head tube is shorter for a slightly more aggressive geometry, but isn't that at the cost of less control? I've always heard the longer the stem the less control you have when you turn. So, for those pros taking the crazy descends and sharp 90 degree turns at a km out, it would seem advantageous to ride a frame that fits them and go with the shorter stem.
I'm 5'9"/175cm and ride a 52 (53cm top tube), with a 12 cm stem. It fits perfectly. (getting into the drops was tricky when i was up at 85 kilos, i've lost weight now, and it's easy.)
Most of steering a bike is leaning it, not heaving on the bars. Moving the bars too much potentially makes the bike less stable and controllable.
Fashionable mountain bikers use tiny stems and massive bars to get down descents no faster than a good rider can get down with 600mm bars and a 12 cm stem. Its partly driven by the mega slack head angles they use to be freeridey and gnar, using a long stem on a 67 head angle is a "bit of a bad idea". I don't know where the read across into road came from.