"Spreading" which will produce optimal cache use is something that depends on dynamic and not static properties of the program, so you'd have to "spread" differently depending on the use patterns. I can't imagine any universal solution.

And most of the programmers make much bigger omissions than those mentioned in this topic. Like using wrong algorithms, wrong libraries, doing too many allocations, having bad structures of the data... So this topic effects are invisible unless you already fixed other issues.