Composition. the worst of the worst soft score offenders. It is a hold-over form 1st edition of 40k. You know, when you could arm your space marines with Shurican Catapults. Back then you could put whatever you wanted on the table. So Comp worked then, when you could make really stupidly overpowered stuff. Now? well now each race has it's own book. no more mixing wargear between xenos and Space