Bloody Rose and Valorous Heart where near auto-picks before. They're still good, but they're a little less good to try and balance the Orders a little more.
So they decided to kick the Bloody Rose into the dirt by down grading their unique strategem and their conviction.
I feel like the rework across the army looks pretty good as a whole. Like Argent Shroud advancing and counting as stationary for all shooting (sprinting Retributors anyone?), OoOML being tweaked so it doesn't work if you heal the unit back to full, making Ebon Chalice actually worth using, ect.
Argent Shroud could already do sprinting Retributors.
When a unit with this conviction Advances, it can fire ranged weapons as if it had moved without Advancing.
Combined with Retributors ignoring movement penalties for shooting (which I imagine is going away), it was a thing before. Argent Shroud just didn't do enough before to warrant being a pick.
And EC is only worth using if you play mono-Sisters. If you're like me and actually want to play an Imperium army (such as bringing guard), EC loses half of its Order Trait and that bothers me.