I'd say that any WH 40k game would almost have to be innately superior to the GoW games just because of how well realized and compelling the universe is. I mean, pretty much any thing set in the 40k universe is going to involve a thematically rich story with big ideas coming into direct conflict with each other. Usually the writers ask things like "Can faith stave off the fear of death and would the fear even be there without the faith?" or "would knowing the future destroy a man?" or "Should a superior man be obligated to help those lesser than him?". In general, that's the sort of stuff that makes great sci-fi fantasy.
What's Gears got? THE COAL TRAIN! WHOO!
What's Gears got? THE COAL TRAIN! WHOO!