> A problem there is that in memory the arrays are of course laid out one after the other, which actually destroys cache locality if you need to access more than 1 property inside a loop (it will need to load back and forth to the different property arrays), so it's a somewhat dumb approach.

Caches are perfectly capable of dealing with more than one stream of data (there are some very specific edge cases you may have to consider), accessing multiple arrays linearly in a loop is generally more efficient than accessing a single array of structs when you don't use almost all the struct elements.