That's an interesting insight, although at present I don't know what Einstein meant about a local ether. It surprises me that he didn't want light to propagate through nothing, in the sense that it seems to me a crucial element of relativity is that if two objects in empty space communicate via light, then the only relevant effect is the relative speed between the objects, not the speed of either relative to the space they are in. The former is unique, the latter is observer-dependent. In this light, the "nothingness" of space is seen as an advantage, since it explains why there is only one velocity of relevance, rather than two.