The way ikkyo through yonkyo are described in Japanese is pretty illuminating.
Ikkyo is also called "ude osae" which can translate to "holding/pressing the arm."
Nikyo is also called "kote mawashi" which can translate to something like "turning/rotating the forearm."
Sankyo is also called "kote hineri" which can translate to "twisting the forearm."
Yonkyo is also called "tekubi osae" which can translate to "holding/pressing the wrist."
So, the basic technical description (ie its Japanese name) of ikkyo does not connote any sense of twisting/turning.
Also interesting, perhaps, is nikyo and sankyo refer to "kote" (which is more properly defined as the part of the arm between the wrist and elbow) whereas yonkyo specifically refers to "tekubi" (which is the wrist or, literally, "the neck of the hand").
In any case, just my thoughts thrown into the discussion here regarding the "proper" pin for ikkyo/nikyo.