I think I've explained my reasons throughout my posts. I think Marshall's place as the "king of fast bowling" over the other big 5, especially the mystique of his extra "skill" being some sort of tiebreaker, is unwarranted. Of course he had to be more skilled. Being shorter makes things harder in the world of fast bowling (if Marshall was Fidel Edwards height, we wouldn't even be having this conversation.) But if the extra skill nets the same end result, why should it be elevated? Steph Curry has to be more skilled than Michael Jordan, but no fool places the former over the latter.
Like, people talk about Marshall's skiddy bouncer, but it's not some ideal that he developed, it's simply the consequence of him being shorter and having a lower release point, while generating similar pace to the other taller members of his quartet. It complemented his teammates nicely (especially when you have a 6 foot 6 Sesame Street character sending them in from the clouds), but it's not some inherent ideal. Similarly, yes he had to master seam and swing movement both ways, and better control. Because it's just harder for him, when your stock ball comes in from a lower height, even at the same speed, it simply won't be as awkward for batsmen to face unless you have that movement.
Finally, to be clear, I'm not trying to take away anything from what Marshall accomplished. IMO, in evaluating his individual performance it puts him as an equal top 5 ATG in the pantheon of quicks.