Non-native english speakers frequently come into the chatroom & ask what "stalled" means. Most of these people seem to understand easily what "on hold" means though. With this in mind, I think it'd be a good idea to change "stalled" to "on hold".
(i say that because this would be a very costly change to make - timewise/complexity-wise, so the bar would be high for changing it / it would need to be for a very strong reason)
*shrug* I had done some looking around & of the other anime/manga list sites which include such a status, about half use "stalled" and about half use "on hold".
Meanwhile, the people in chat who are confused about "stalled" don't appear to be familiar with/have used MAL (though I didn't specifically ask).
If it's not easy to change the label on the site, I would suggest putting up a poll somewhere (probably facebook would get the most results) & get a better idea what most people think.
Let me give my 0.02€: the word “stalled” is not obvious for non-native-speakers, and if we've heard it at all, we'll associate it with “can't get X to move” (stalled car, stalled download) rather than intentionally stopped. On the other hand, “on hold” is obvious, MAL or not.
This might be something better left to poll foreign people about. Or maybe a cute little Anime-Planet tutorial could be made that includes explaining the status markers?