Their could be alternative mapping options for many if not all controllers, the question really is assessing whether someone's idea of a alternative mapping is feasible in the grand scheme of things, meaning are their differences that warrant this mapping that also will benefit a large percentage of users. obviously is a long winded affair to do duel mapping for all controllers but some indeed deserve a secondary mapping.
Now my idea for secondary mapping usually means one that does away with video for those that need more in-depth control for the purpose of mixing instead of the controls wasted for video, but in relation to another mapping for video making a second mapping does seem a little overboard, so I am thinking in this case the existing mapping for audio and video just needs some additions too it if they are indeed feasible, addition by the way of secondary or third function of controls using mods or what ever way the programmer thinks is feasible in relation to the these wishes for extra control.
Now I know it can be difficult some time to explain things without having to write many words in explanation, so what I would suggest bigworm1063 if its really important too you, please explain what you are missing and maybe what benefit these extra would have too you, and if doable this can be discussed further. At the moment the controller mappings are only being done by one person who is not a direct worker for mixvibes, so controller availability could prove tricky. But either way this discussion would be interesting, so the information I mention that needs giving is the first step.