Given that Wonders now occupy an entire tile by themselves, and they've already confirmed that it will not be possible to damage them, I'm hoping somebody will create a mod where it will be possible to damage them. If nobody does, I may have to learn how to mod and try to create it myself.
Mind you, I only have a vague idea of how it should work. I know it shouldn't be possible for just any old military unit to walk by and destroy a Wonder, because then every Wonder would get destroyed every time, and that would be no fun. If razing cities Civ V-style is still in, perhaps Wonders would just naturally get destroyed during that process? I don't know, but I want to see destroyed Wonders remain on the map. They'd lose whatever benefit they had, but they should still contribute toward Tourism. And they shouldn't change into a generic "ruins" graphic, either--I'd want to see them turn into actually ruined versions of themselves, such that we have this:
turning into this:
Of course, that would require collaboration with a talented artist, since I assume learning how to alter the Wonder graphics in that way would take a lot more time and effort than simply learning how to script a method for allowing Wonder destruction at all.