The transformation system has been a pain point for us, it was difficult to maintain and could cause some major rendering problems in some GPU vendors if used even sightly differently. It's used for animating, instancing and positioning models.
We've previously moved that system to Constant Buffers but that also caused it's own set of problems on editor tools and things that need a lot of transformation slots at once like cloth.
I've decided to rip it all apart and rework it using structured buffers, it gives much better stability in complex scenes.
It also makes it much easier for us now if we need to maintain it, but I think it's in a point where we don't even need to iterate much on it anymore.
