We currently have the ukemi, which is the Japanese martial arts term for falling technique. To be more English language friendly, should we make a falling and make ukemi a synonym? The current situation is fine for students of Japanese martial arts, but those coming from other traditions (TKD, for example) have no obvious way of finding this.
This should make it easier for all users to find the right concept.
That would probably not be a good idea.
I actually was writing this question and was surprised to find that falling was not an ukemi synonym, and it was also not an existing tag. This could be helpful to new users who may not have "ukemi" in their vocabulary but would like to ask a question about falling.
However, since ukemi is Japanese-specific and falling is an umbrella term, I would argue that if they do become synonyms, falling should be the main tag, with ukemi being it's synonym. It wouldn't make sense to pick the main tag to be a term that only applies to some martial arts.
"Falling" and "ukemi" aren't necessarily the same thing. While ukemi is part of falling, it is only a very small piece. Ukemi only refers to the way of safely falling taught in Japanese arts, whereas falling could include any style. It's the same reason why kata and forms (as Slugster mentioned), or striking and punching aren't synonyms: one is an umbrella for the other; they're not the same exact thing.
I'm not strongly opposed to the idea, I just don't think that we should force one culturally-specific term onto everyone, especially if they aren't asking about those styles.