Especially since the term qi gong itself is not very old.
We should be careful here-- are you saying that we shouldn't use the term "qi gong" to refer to old things like the Ba Duan Jin* or the exercises in the Yi Jin Jing?
Quite the contrary, these things are often pointed to as definitive examples of what qigong is. I guess my point is that there is an old, widespread idea of physical/mental cultivation that the term qigong refers to. You have to do it right (intention/yi is not visible, but it is intimately linked to qi/ki, so it goes without saying that some people may do a qigong without
the right intent by only imitating the movement - this is empty and wrong). These methods may predate any one name. I believe qi gong is a term that intends to refer to these methods, and I advocate for its general use.
*This gets a bit back on topic - Tamura sensei showed the Ba Duan Jin before seminars. It is on video on the net, and he was asked about it in an interview. There, he very nicely described how he rationalizes using these exercises within his training. That is, he said O-sensei would recognize value in "foreign" methods, and would say "this is good" and would be in favor of doing it -- or if he didn't see value he would say "this is bad." Thus, anyone following in his footsteps should learn to distinguish "good" methods for body, mind, and ki cultivation and should feel free to practice them.