It's a bit different I think because the roof itself was never "preserved the best we can", it's "just" a sort of fantasy roof built at a time when Violet le Du

It's a bit different I think because the roof itself was never "preserved the best we can", it's "just" a sort of fantasy roof built at a time when Violet le Duc rebuilt many monuments using his imagination and fantasy with little historical basis. I can't really say which would be best myself, but the point is since the roof is already the not historical part of the cathedral, it makes little sense to rebuild it exactly in that precise not historical way. Instead, it could keep being the one evolving part of the building.