[Dolby]

lua is just the language used and yes both WoW and ESO use LUA for the UI, so do many other games. It doesn't mean you can do the same things in both games. The game developers control the API addon authors use and that is what is blocking this from happening. There is nothing in the API that would support something like this. Now some one might be able to figure out a way to swap spells/abilities in and out really fast but thats about it.

Also if some one finds a bug or work around that allows this to happen I'd bet ZeniMax would be fairly quick to take away whatever part of the API it is that allowed it. So all that effort would be squashed in a quick patch by ZeniMax.